Elastic seal, face mask assembly and CPAP system

Abstract

A face mask assembly (1500) has an elastic seal (1600) and a mask body (1700). The elastic seal (1600) comprises a first tubular member (1601), a bridging portion (1602) and a second tubular member (1603). The elastic seal is prefabricated such that it has a single stable state configuration, wherein the single stable state configuration is a donning configuration. The face mask assembly (1500) may be used in several applications including personal protective equipment (PPE), continuous positive airways pressure (CPAP) ventilation and mechanical ventilation of the lungs using a minimally invasive oropharyngeal or nasopharyngeal airway.

Description

[0001]ELASTIC SEAL, FACE MASK ASSEMBLY AND CPAP SYSTEM The present invention is directed towards an elastic seal for a face mask assembly, a face mask assembly, and a CPAP system having a face mask assembly. Face masks are and may be used in several applications including personal protective equipment (PPE), continuous positive airways pressure (CPAP) ventilation and mechanical ventilation of the lungs using a minimally invasive oropharyngeal or nasopharyngeal airway. BACKGROUND Face mask seals are desired to form an air-tight seal around the nose and mouth of the wearer so as to effectively control the ventilation of human or animal wearer of the face mask. Face mask bodies are desired to perform a filtering function and may also include a valve. The combination of a filter and valve can provide two-way protection for both the wearer and the surrounding environment against microbial and particulate contamination. Existing face mask seals follow two main designs. A first type of face mask seal forms a parallel seal with stretching securement. This type of face mask seal is commonly seen in surgical face masks. The parallel seal relies on the mask margin overlapping with the wearer’s skin for a variable width to form the seal. A mask using the parallel seal is typically made of one or more flat panels of flexible fabrics cut into specific shapes and joined along certain edges to create a three-dimensional form that accommodates the nose protuberance and follows the sagittal curvature of the human face to the chin. A piece of malleable (usually made of metal) strip may be embedded in the upper rim of the mask for crimping around the nose bridge so that the mask margin “hugs” the two shorter edges of the nose-cheek triangles. The parallel seal is typically secured to the wearer’s face by stretching its margin backwards with straps. This is referred to as “stretching securement”. The parallel seal mask is based on approximation of three-dimensional geometry with flat panels. Even though the malleable nose crimp helps the mask hug the nose-cheek triangles and the flexible panels improve the mask’s ability to conform to the human facial contour, the fit is unlikely to be perfect and the parallel seal can leak significantly. However, the parallel seal exerts relatively little pressure on the wearer’s face and is made of softer materials. As a result, the parallel seal mask can be worn for a long time without causing skin damage. A second type of face mask seal forms a perpendicular seal with compressive securement. This type of face mask seal is commonly seen in N95 respirators. The “perpendicular” seal is typically made of a semi-rigid plastic material formed into a specific three- dimensional shape to match the human facial contour. The nose-cheek triangles are typically filled by triangular-shaped flanges in the seal. To improve the fit and wearer’s comfort, the seal margin may be lined with compressible padding materials that deform under pressure to plug the gap between the semi-rigid mask margin and the human facial contour. The perpendicular seal is typically compressed against the wearer’s face from the front by pulling its base backwards with straps. This is referred to as “compressive securement”. The perpendicular seal may need to exert considerable pressure on the wearer’s skin to prevent air leakage. The softer deformable padding material may not disperse the elevated pressure over an area much wider than the harder semi-rigid seal margin, resulting in indentations and even pressure ulcers on the wearer’s face. Because the mask is semi-rigid and inelastic, it is less able to deform to conform to changes in the shape of the wearer’s face. Even though the parallel seal and perpendicular seal masks can deform to accommodate variation in the shape of the human wearer’s face to an extent, their constituent materials are inelastic and cannot significantly change in dimensions. When the wearer opens his or her mouth (e.g., in order to speak), the mask may not lengthen vertically enough so that the chin slips out of the seal. The mask will also become narrower horizontally, pulling the seal margin forwards and away from contact with the cheeks, creating lateral gaps around the seal. The soft tissues of the cheeks move towards the midline as they are stretched, further widening the lateral gaps around the seal. Furthermore, an additional problem associated with the usage of face masks and the sealing of such masks around the user is that the tightness of any seal around an object could be compromised if the seal relies mainly on friction to prevent slippage and lubricants such as water or oil slowly accumulating at the seal-object interface. This situation will occur if the seal is part of a face mask, and the object is the face of a human being or any other animals that sweat and secrete oil from their skins. The human face is highly variable in shape. Multiple face mask models may need to be produced, which greatly increases the manufacturing complexity and costs. Fit testing also needs to be conducted to match each wearer with a suitable mask model. Fit testing requires special equipment and trained personnel to conduct and is time consuming (up to 30 minutes for each test subject). When a large workforce needs to be fit tested, the exercise can be extremely disruptive and very costly in terms of trained fit testing personnel, specialist equipment and lost productivity. Existing face mask filters are typically made of one or more layers of porous materials such as non-woven fabrics, melt blown fabrics; but also woven fabrics like cotton and other material. The filter may form the entirety or majority of the mask body or may be confined to a rimmed area of the mask body. Some of the filters can be replaced with disposable inserts. The fabrics forming the bulk of the mask and the filter holder may be washed and reused. Some of the filters are semi-rigid and could be moulded into specific shapes to form the mask. Other filters are flexible. A problem with replaceable filters is that they require a further seal in addition to the mask seal that forms the sealing perimeter around the nose and mouth of the wearer. The further seal is required to form the seal between the filter and the mask body. This increases the complexity and cost of achieving air tightness. Most filters are formed from fibres with gaps that are able to block the passage of fine particles but unable to block the microbial or particulate agents. To block a high percentage of particles, the filter needs to be thicker, increasing the airflow resistance and making it harder for the wearer to breathe. With use, more particles are trapped between the filter fibres and the airflow resistance rises, making it harder for the wearer to breathe. The particles trapped between the filter fibres cannot be efficiently removed. The filter thus has a limited working life span and must be replaced to reduce airflow resistance. Flexible fabric mask bodies can collapse and wrap around the nose and mouth of the wearer during deep inspiration. This can reduce the efficiency of inhalation as some of the energy is used to deform the mask body rather than move air, increases the airflow resistance as only the small areas of filter directly over the wearer’s nostrils and the mouth may be available for air movement, increases contact between the inside of the mask and the wearer’s face and risk of contamination by water droplets or other materials deposited on the inside of the mask, and causes discomfort to the wearer. Moisture can condense on and within the filter from the water vapour exhaled by the wearer. The water droplets provide a moist environment for bacteria and fungi to grow. The wearer’s mouth and tongue can become contaminated if they touch the inside of the mask by accident or if the mask / filter collapses under negative pressure. Flexible fabric mask bodies collapsing during inhalation can be mitigated by putting a semi-rigid frame to prop up the mask body, adding to the bulk, weight and rigidity of the mask. One set of filters that are particularly common within the field of face masks are high efficiency particulate adsorbing (HEPA) filters. The vast majority of commercially available HEPA filters are made of non-woven fibres, and are configured to block particle entry namely by: 1. Interception – wherein particles, moving via diffusion or convention, are intercepted through collision of the particles with the fibres. 2. Impaction – wherein the particles are larger than the interstices formed between the filter fibres themselves. 3. Electrostatic attraction – wherein electrostatic attraction is used to capture the particles onto the filter fibres. The interstitial spaces between the fibres in a HEPA filter are typically larger than the sizes of the particles that the filter is designed to block. Accordingly, to increase the filtration ‘efficiency’ (the proportion of particles of a certain size that would be blocked by the filter) by physical means (interception and impaction), the filter must be thick (i.e. a depth filter) to increase the probability the particle will be blocked by a filter fibre. An issue with such an approach is that the thicker filter inevitably increases the airflow resistance, which would be a major concern for a non-powered respirator / face mask as the human wearer needs to generate the force needed to vent the apparatus. As such, a face mask with a thick filter is not suitable for prolonged use as the respiratory muscles of the human wearer would tire out. Thus, the HEPA filters used in the current non-powered respirators / face masks rely heavily on electrostatic attraction for removing particles from air so that the filter could remain acceptably thin. In order to avail of this electrostatic attraction mechanism, the charge is artificially placed during manufacturing of masks incorporating non-woven fibre HEPA filters. Each face mask only has a finite amount of electrostatic charge (highest immediately after manufacturing), which will dissipate during use on contact with particles or spontaneously during storage. The HEPA filters used in the current FFP3 face masks can therefore not be reused (even if they could be cleaned of all particles embedded between the fibres) as the store of exhausted of electrostatic charges needs to be replenished and this is not technically feasible at this moment in time. Face mask valves open during exhalation and close during inhalation. Such valves may be referred to as exhalation valves. Existing face mask valves are contained within a flat rigid cage embedded in the mask. The side of the cage has slits to allow air movement. The bottom of the cage is embedded in the mask and has an orifice spanned by struts. The orifice is covered by a semi-rigid flap either adherent to one side of the cage bottom or mounted on a short stem inserted through the centre of the struts. The struts stop the flap from falling through the orifice into the interior of the mask. When the external (outside the mask) pressure is equal to or above the internal (within the mask) pressure, the flap covers the orifice in the cage and the valve is shut for airflow. When the internal pressure rises above the external pressure (such as when the wearer exhales), the flap lifts off from the orifice and air flows outwards from within the mask through the slits in the cage. These exhalation valves are typically mounted on the front or sides of the face mask. A problem with existing exhalation valves is that the exhaled air is not filtered. While this may lower the airflow resistance the wearer has to overcome during exhalation, the unfiltered exhaled air exposes the people and the environment to potential contamination originating from the wearer. Additionally, issues may be more prevalent in certain applications which require face mask assemblies. One such application is the application of face mask assemblies in CPAP therapy. Generally, CPAP face mask assemblies typically fall into two categories, namely nasal and full- face which refers to whether the face mask assembly covers the nose alone, or both the nose and the mouth. Typically, CPAP masks achieve a seal with the face of a wearer by pressing a soft cushion that is mounted to a mask body. The mask body in these examples is not used for filtering purposes; rather, the mask body comprises a mask frame for structural support (e.g. to provide structural support to the soft cushion) and attachment portions for connecting the mask body to the CPAP headgear. The mask body also typically has a port for insertion of components for connecting the CPAP mask assembly to a CPAP machine. In these applications, the mask body in CPAP applications has to be sufficiently rigid to withstand to pull force it would be exposed to in use, and can be made in as a singular piece, or can be in a modular configuration. When the mask body is made as a singular piece, the mask body may be moulded from a rigid or semi-rigid plastic such that the soft cushion and mask body are mounted or mountable together. When the mask body is in a modular format, the mask body may be split into a first mask frame member that is adhered to the cushion and second mask frame member with attachment points for attaching the headgear to the mask body. However, these conventional approaches are not without issue. Firstly, in the modular format, there is the risk that, upon exposure to solvents such as isopropyl alcohol during cleaning, the mask body and cushion may separate, or alternatively, the seal formed between these components may be jeopardised over time from repeated cleaning and / or use. Conversely, in the singular mask body approach, it can be difficult and expensive to mould the frame over the cushion to obtain a proper airtight connection between the mask body and cushion, and vice versa. Furthermore, in such face mask assemblies, the harnesses used tend to be single-piece harnesses that have straps joined together at fixed angles, either via sowing or ultrasonic welding. One reason for this is that the harness needs to exert sufficient force to push the CPAP cushion flush with the user’s face to achieve a good seal. However, this rigid framework necessitates a plethora of different harness designs to accommodate different head sizes, which adds to the manufacturing costs for making such products. Additionally, users may need to try multiple sizes until they obtain a best-fit harness that suits their head shape, which can prove cumbersome. In addition, the harnesses used for these CPAP face mask assemblies, whilst being generally rigid, must have some elasticity to accommodate changes in the shape of the wearer’s head, such as when a user opens their mouth. These changes, however, may result in abrasion during usage of these face mask assemblies. Furthermore, such abrasion may be made worse by the elasticity of these straps. Upon application of tension, the strap will narrow and also lengthen. In this condition, the strap has a greater tendency to twist, which reduces the surface area in contact with the skin. With this tangential tension being applied, a normal force is also generated perpendicular to the this tangential tension, which, in a twisted state, exacerbates the abrasion due to the greater pressure being applied. In addition to the abovementioned issues with CPAP face mask assemblies, another issue is the problem of ‘dry mouth’ which causes issues such as dental decay and bad breath. With prolonged CPAP therapy, the usage of pressurised air may lead to accelerated evaporation of moisture in saliva. As a result, neutralising agents, such as sodium hydrogen carbonate, that function to neutralise the acidity generated by dental bacteria, may become insoluble and thus inoperative in function. Overtime, this may result in dental issues as mentioned above. One such approach to tackling this issue is to incorporate a humidifying unit into CPAP machines or CPAP tubing; however, this approach still presents the risk of bacterial or fungal infection occurring. Other issues, in addition to the above, for CPAP mask assemblies include symptoms such as peri-orbital oedema, which results from the compression of veins causing the drainage of lymphatic fluids from the soft tissues around the eyes, as well as ear-pain due to the high pressure needed to maintain airways patency creating a large pressure gradient across the eardrum. It is an object of the present disclosure to provide an improved face mask construction. It is an object of the present disclosure to provide an improved seal such as for use as a face mask seal. It is an object of the present disclosure to provide an improved mask body construction for a face mask. SUMMARY There is provided an elastic seal, face mask assembly and CPAP system as set out in the accompanying claims. Other features of the invention will be apparent from the dependent claims, and the description which follows. According to a first aspect of the disclosure, there is provided a face mask assembly comprising an elastic seal and a mask body, the elastic seal comprising an inner tubular member, a bridging portion and an outer tubular member. Ideally, the face mask assembly comprises a mask base. Ideally, the elastic seal comprises the mask base. Ideally, the bridging portion bridges between the inner tubular member and the mask base or the outer tubular member. In use, the outer tubular member is optional when the elastic seal is used within a face mask assembly. In one embodiment, the elastic seal and mask base may be integrally formed. In another embodiment, the elastic seal is fixable to the mask base. The mask base may be homogenously formed with the elastic seal. The mask base and the elastic seal may be homogenously formed as a single piece. The mask base may comprise a mask base aperture. The mask body may be insertable into the mask base aperture. In the inverted configuration, the mask base aperture may be distal to the sealing perimeter formed around the nose and mouth and / or eyes of a wearer. Ideally, at least part of the seal is invertible. More specifically, at least part of the elastic seal is invertible to form a sealing perimeter around the nose and mouth of a wearer. Additionally, at least part of the elastic seal is invertible to form a sealing perimeter around the mouth and nose and / or eyes of a wearer. Ideally, the at least part of the elastic seal that is invertible to form a sealing perimeter is preferably the inner tubular member. Ideally, the inner tubular member comprises an inner tubular through bore. Preferably, the inner tubular member is configurable to form a sealing perimeter around the nose and mouth of a wearer. Additionally, the inner tubular member is configurable to form a sealing perimeter around the mouth and nose and / or eyes of a wearer. Ideally, the inner tubular member is invertible. Ideally, the inner tubular member is invertible to form a sealing perimeter around the nose and mouth of the wearer. Ideally, the inner tubular member is invertible to form a sealing perimeter around the nose and mouth and / or eyes of the wearer. Ideally, the inner tubular member has a cross-section, and in preferred embodiments, a circular cross-section. Ideally, the inner tubular member comprises a first inner tubular member surface and a second inner tubular member surface. Ideally, the elastic seal is invertible from a rest configuration to a deployed configuration. More specifically, the inner tubular member is invertible from a rest configuration to a deployed configuration. By “deployed configuration”, it will be understood that the inner tubular member is arranged for forming a sealing perimeter around the mouth and nose and / or eyes of a wearer. In arrangements where the inner tubular member is invertible, the deployed configuration may also be referred to as the inverted configuration. Ideally, in the rest configuration, the first inner tubular member surface is an inner tubular surface, and the second inner tubular member surface is an outer tubular surface. In some arrangements, in use, the inner tubular member may be invertible from the rest configuration to the inverted configuration such that the second inner tubular member surface is inverted from being an outer tubular surface to an inner tubular surface adapted for forming a sealing perimeter around the nose and mouth of a wearer. Additionally, in use, the inner tubular member may be invertible from the rest configuration to the inverted configuration such that the second inner tubular member surface is inverted from an outer tubular surface to an inner tubular surface adapted for forming a sealing perimeter around the nose and mouth of a wearer and / or eyes of a wearer. Ideally, in the deployed configuration, a shape-receiving opening is locatable at an end of the inner tubular member. Ideally, the shape-receiving opening is configurable to receive the face of the wearer of the mask. Ideally, the shape-receiving opening is configurable to be flexible and adaptable to the shape being received. The shape-receiving opening may be a first opening. The mask base aperture may be a second opening. Preferably, in the deployed configuration, the elastic seal, and in particular the inner tubular member, is configurable to form an effective sealing perimeter for a variety of facial shapes and is able to maintain the sealing perimeter as the wearer opens their mouth. Preferably, in the deployed configuration, the elastic seal is configurable to seal around a shape comprising a first contour comprising a convex curvature and a second contour comprising a concave curvature. Preferably, in the deployed configuration, the elastic seal is configurable to seal around a shape comprising a first contour comprising a convex curvature and a second contour comprising a convex and concave curvature. Ideally, the inner tubular member is configurable to seal around a contour comprising a convex and concave curvature. Ideally, in the rest configuration, the first inner tubular member surface comprises a smaller surface area than the second inner tubular member surface. Ideally, in use, the inner tubular member is invertible from the rest configuration to the deployed configuration, wherein the inner tubular member is configurable to form a bend to minimise the potential energy stored in the elasticity of the seal. More specifically, in the deployed configuration, the bend comprises a concave curvature. Ideally, the inner tubular member, in the deployed configuration, comprises a bent portion. The bent portion is a concave bent portion. The bent portion is adjacent to the bridging portion of the elastic seal. Advantageously, in the deployed configuration, the recoil of the bend exerts a force to urge the inner tubular member to seal around the nose and mouth of the wearer. More specifically, in the deployed configuration, the recoil of the bend exerts a force to urge the inner tubular member to seal around a shape comprising convex and concave curvature such that the inner tubular member thereby forms an effective sealing perimeter around the convex and concave curvature of the shape. Advantageously, in the deployed configuration, the elastic seal, and more specifically, the inner tubular member is configurable to provide concentric contraction around and centripetal radial compression across the inner tubular member to increase the friction between the elastic seal and face of the user and to prevent the elastic seal from slipping off the face of the user. In preferred embodiments, the inner tubular member comprises an inner tubular member length and the outer tubular member comprises an outer tubular member length. Ideally, the inner tubular member length may be the same as, or different to, the outer tubular member length. Ideally, the inner tubular member and the outer tubular member are axially aligned and extend axially in the same direction. Ideally, the face mask assembly comprises means for preventing slippage of the elastic seal. Ideally, the elastic seal comprises means for preventing slippage of the elastic seal. Ideally, the means for preventing slippage of the elastic seal is configurable to grip an object, such as the face of a user of the face mask assembly. Ideally, the means for preventing slippage of the elastic seal is configurable to grip the user’s face when the elastic seal is in the deployed configuration. Ideally, the means for preventing slippage of the elastic seal comprises at least one protrusion. Ideally, the at least one protrusion is locatable on the inner tubular member, and more specifically, the first inner tubular member surface of the inner tubular member. Ideally, the at least one protrusion is formable from the inner tubular member. Ideally, the at least one protrusion is at least one ridge or at least one flange. The at least one ridge or at least one flange may also be referred to as at least one spline. In some arrangements, the at least one protrusion may extend from the bridging portion to the end of the inner tubular member that is arranged, in use, to form the sealing perimeter on the face of a wearer of the face mask assembly. In other words, the at least one protrusion may extend along substantially the entire inner tubular member length. Alternatively, the at least one protrusion may partially extend along the length of the inner tubular wall. For example, in some arrangements, the at least one protrusion may be arranged to extend from a first end of the concave bent portion to a second end of the concave bent portion. The first end of the concave bent portion may be located adjacent to the bridging portion. The second end of the concave bent portion may be located adjacent to the padding means. In other words, the concave bent portion may comprise the at least one protrusion. Ideally, in the deployed configuration, the means for preventing slippage of the elastic seal is configurable to exert pressure such that the elastic seal, and more specifically, the inner tubular member presses against the user’s face. Advantageously, the means for preventing slippage of the elastic seal is configurable to stop the inner tubular member from rolling up and lifting off the user’s face in use. Yet further advantageously, the means for preventing slippage of the elastic seal is configured to mitigate the longitudinal retraction of the inner tubular member when the inner tubular is stretched circumferentially e.g. in the deployed state on the face of a wearer of the face mask assembly during. Ideally, the elastic seal may comprise a padding means. The padding means may be locatable on the inner tubular member. The padding means may be locatable on the second inner tubular member surface of the inner tubular member. The padding means may be formable from and / or as part of the inner tubular member. The padding means may be formable from and / or as part of the second inner tubular member surface of the inner tubular member. The padding means may extend along at least part of the length of the inner tubular member. The padding means may comprise a padding section that is functionable as a reinforcement padding section for reinforcing the inner tubular member. The at least one padding section may therefore be referred to as the reinforcement padding section. The reinforcement padding section may be configured to stabilise the inner tubular member to remain in the deployed configuration. The reinforcement padding section may be configured to prevent the retraction of the elastic seal on the face of a wearer of the face mask assembly. The reinforcement padding section may be configured to prevent the pressing down of the elastic seal on the face of a wearer of the face mask assembly. The reinforcement padding section may be arranged to distribute the compressive stress associated with the inner tubular member being in the deployed configuration. The reinforcement padding section may be extend from the skirting portion of the inner tubular member to the concave bent portion of the inner tubular member. The reinforcement padding section may be substantially located on the outer surface of the inner tubular member when the inner tubular member is in the deployed configuration. The reinforcement padding section may have an undulated profile. The reinforcement padding section may span at least part of or substantially the entirety of the circumference of the inner tubular member. The reinforcement padding section may be homogenously formed as part of the inner tubular member. The reinforcement padding section may comprise one or more pairs of reinforcement pads. Each pad of the one or more pairs of reinforcement pads may have a wave-like profile. Each pad of the one or more pairs of reinforcement pads has a variable thickness. The one or more pairs of reinforcement pads may comprise a first pair of reinforcement pads. The reinforcement padding section, and, more particularly, the one or more pairs of reinforcement pads may comprise a second pair of reinforcement pads. The reinforcement padding section, and, more particularly, the one or more pairs of reinforcement pads may comprise a third pair of reinforcement pads. Each pad of the one or more pairs of reinforcement pads may have substantially equal maximal thickness. In use, this equivalence in maximal thickness assists in distributing the compressive stress arising from the deployment of the inner tubular member in the deployed configuration. In arrangements where the one or more reinforcement pads comprises two or more pairs of reinforcement pads, each pair of reinforcement pads may be equispaced angularly about the circumference of the inner tubular member. In use, this assists in evenly distributing the compressive stress arising from the deployment of the inner tubular member in the deployed configuration. This further assists in preventing the retraction of and pressing down of the elastic seal on the face of a wearer of the face mask assembly and further assists in stabilising the elastic seal in the deployed configuration. The one or more pairs of reinforcement pads may be located on the outer surface of the inner tubular member when the inner tubular member is in the deployed configuration. In an advantageous arrangement, the padding means may comprise a nose pad. The nose pad may be homogenously formed as part of the elastic seal, and more particularly, the inner tubular member. The nose pad may be configured to have a preformed shape. The nose pad may be located on the inner surface of the inner tubular member when the inner tubular member is in the deployed configuration. The nose pad may comprise a first nose pad portion and a second nose pad portion. The nose pad may be dimensioned such that an arch-shaped recess is defined by at least part of the first nose pad portion and at least part of the second nose pad portion. The first nose pad portion may be configured, in use, to plug a respective first concavity located on a first side of the nose bridge. The second nose pad portion may be configured, in use, to plug a respective second concavity located on a first side of the nose bridge. The nose pad may be configured, in use, to plug the concavities formed between the convexities on either side of the nose bridge. The nose pad may be adapted to seal around the nose bridge of the wearer of the face mask assembly. The nose pad may be configured, in use, to seal around the nose bridge of wearer of the face mask assembly such that curvature over the nose bridge is reduced. The nose pad may be operable to modify the contour of the nose bridge from a mixed convex-concave contour into a substantially convex contour. In other words, the nose pad may be operable to modify the contour of the sealing perimeter formed around the nose and mouth of a wearer from one with a mixed convex-concave contour to one with a substantially convex contour. In this way, the pressure exerted on the nose bridge is reduced. Advantageously, the nose pad may be configured to reduce and redirect the normal pressure for a given tangential tension around the facial contour. The nose pad may be configured, in use, to extend along at least part of the nose bridge to distribute the normal force exerted on the nose and cheek of a user of the face mask assembly. Advantageously, this distribution of normal force reduces the pressure exerted on the user of a face mask assembly, thereby improving the comfort for the user. The nose pad may be configured, in use, to rest on the alae of the nose of a user of the face mask assembly. The first nose pad portion and the second nose pad portion may each comprise a resting portion that is arrangeable, in use, to rest on a respective ala of the nose of wearer of the face mask assembly. Beneficially, the resting of the nose pad on the alae aids in stabilising the position of the face mask assembly on the face of a wearer of said assembly. Ideally, the padding means comprises a first padding section. The first padding section may be configured, in use, to plug the concavities formed between the convexities in the nose- mouth contour i.e. on either side of the nose bridge. The first padding section may comprise a first major pad and a second major pad. In the inverted configuration, the first major pad may be configured to plug a corresponding first concavity of the nose-mouth contour. In the inverted configuration, the second major pad may be configured to plug a corresponding second concavity of the nose-mouth contour. By plug, we mean that, in use, the pads will protrude into the corresponding concavity and seal the gap formed by these concavities in the nose-mouth contour. Ideally the padding means comprises a second padding section. The second padding section may comprise an undulated padding section that is configured, in use, to plug facial hair between the undulations of the undulated padding section. Beneficially, in embodiments where the elastic seal comprises at least one spline, the padding means is configured, in use, to distribute the circumferential stress more evenly around the inner tubular member to avoid abrupt transition in stress adjacent to at least one spline. This reduces the risk of any tear arising from the circumferential stress associated with employment of the elastic seal in the inverted configuration. Yet further beneficially, the padding means may be configured to mitigate longitudinal retraction occurring during circumferential stretching of the inner tubular member in use. This counteracts Poisson deformation during employment of the elastic seal, thereby enabling the elastic seal to form a tighter seal around the nose-mouth contour of the user. Ideally, the outer tubular member may be partially collapsible. The outer tubular member collapsibility may be adjustable. The outer tubular member may comprise a first outer tubular member surface and a second outer tubular member surface. The first outer tubular member surface is an inward-facing surface. By inward facing, it will be understood that is surface is contactable with air being breathed in and out of the face mask assembly during usage of the face mask assembly. The second outer tubular member surface is an outward-facing surface. The outer tubular member may be partially collapsible in use to create folds in the inward facing surface. Beneficially, the folds increase the surface area of the inward facing surface of the outer tubular member so as to increase the condensation of moisture on this surface. In CPAP applications users of conventional CPAP face masks may suffer discomfort from dry mouth and dry nose. In the present disclosure, the increased condensation arising as a result of the folds humidifies the air breathed in by a user of the face mask assembly, thereby mitigating or obviating such discomforts. Furthermore, in CPAP applications, the use of a separate humidifying unit is not necessary, as the trapping of moisture using the folds enables a user to humidify the internal volume of the face mask assembly. Ideally, the outer tubular member comprises a control means for adjusting the collapsibility of the outer tubular member. Ideally, the control means for controlling the collapsibility of the outer tubular member may comprise one or more outer tubular member splines. The one or more outer tubular member splines may be homogenously formed as part of the outer tubular member. The collapsibility of the outer tubular member may be adjustable by varying the number of splines and / or stiffness of the splines incorporated into the outer tubular member. Optionally, the elastic seal, and in particular, the inner tubular member comprises a skirting portion. The skirting portion is locatable on the perimeter that is functionable, in use, to form the sealing perimeter around the face of a user of the face mask assembly. Beneficially, the skirting portion is configured to stop the inner tubular member retracting longitudinally when circumferentially stretched in the deployed configuration, thereby mitigating the Poisson effect associated with the stretching of such an elastic seal. Yet further beneficially, the skirting portion, in use, is operable to seal around the nose-mouth contour and to plug gaps formed between and within pads forming part of the first padding section and the second padding section. Yet even further beneficially, the skirting portion is configured to protect the sealing perimeter from tearing in use. The skirting portion may be configured to seal around the face of the user of the face mask assembly in the sagittal plane. In some embodiments, the skirting portion may comprise a first skirting padding section and a second skirting padding section. The first skirting padding section may be in proximity with the first padding section of the inner tubular member. The second skirting padding section may be in proximity with the second padding section of the inner tubular member. The first skirting padding section and the second skirting padding section may be arranged to consolidate the seal around the bridge of the nose of a wearer of the face mask assembly. Ideally, in the rest configuration, the inner tubular member is in a low energy state. In the rest configuration the skirting portion is in a high energy state. In embodiments where the elastic seal, in the rest configuration, comprises an inner tubular member in a low energy state and a skirting portion in a high energy state, the rest configuration is a stable configuration and may be referred to as a first stable state configuration. Ideally, in the deployed configuration, the inner tubular member is in a high energy state. In the deployed configuration, the skirting portion is in a low energy state. In embodiments where the elastic seal, in the deployed configuration, comprises an inner tubular member in a low energy state and a skirting portion in a high energy state, the deployed configuration is a stable configuration and may be referred to as a second stable state configuration. Beneficially, the deployed configuration being a second stable configuration enables the user of the face mask assembly to easily put on the face mask assembly. In absence of a skirting portion in the inverted configuration, the inner tubular member has a tendency to revert to the low energy configuration in the form of the rest configuration, making it more difficult to apply the elastic seal to an object. The inner tubular member may comprise means for stabilising the elastic seal in the deployed configuration. The means for stabilising the elastic seal in the deployed configuration may be configured to reinforce an upper portion of the inner tubular member. The means for stabilising the elastic seal in the deployed configuration may comprise the skirting portion and / or the padding means (or a component thereof) and / or the at least one protrusion of the inner tubular member. In some arrangements, wherein the inner tubular member is switchable between a first stable state configuration and a second stable state configuration, the means for stabilising the elastic seal in the deployed configuration may be configured to bias the inner tubular member towards the second stable state configuration. Ideally, the face mask assembly may comprise a means for absorbing fluids. Preferably, the elastic seal may comprise the means for absorbing fluids. Ideally, the means for preventing slippage of the elastic seal may comprise the means for absorbing fluids. Ideally, the means for absorbing fluids is configured to absorb fluids secreted by a user of the mask and / or exhaled by a user of the mask. Ideally, the means for absorbing fluids is configured to absorb moisture and / or oil. Ideally, the means for absorbing fluids is configured to prevent slippage of the face mask assembly by absorbing fluids secreted and / or exhaled by a user of the face mask assembly. In use, the means for absorbing fluids is configured to capture fluids secreted by the user of the face mask assembly, such as oil and / or sweat for example. Ideally, the means for absorbing fluids is configured to capture exhaled moisture, and in particular, exhaled moisture that has condensed. Advantageously, this enables the face mask assembly, and more specifically, the elastic seal to stay affixed to the face of the user in use without slippage over time due to accumulation of moisture and / or oil from use. In some embodiments, the means for absorbing fluids is adherable to the skin of the user. In some embodiments, the means for absorbing fluids is interposed between the elastic seal and the skin of the user. In some embodiments, the means for absorbing fluids is interposed between the elastic seal in the deployed configuration and the skin of the user of the face mask assembly. In some embodiments, the means for absorbing fluids is interposed between the sealing perimeter of the elastic seal and the skin of the user of the face mask assembly. In some embodiments, the means for absorbing fluids is locatable within the internal volume defined between the mask body and the wearer. In some embodiments, the means for absorbing fluids is interposed between the elastic seal and the skin of the user and also locatable within the internal volume defined between the mask body and the wearer. Ideally, the means for absorbing fluids is configured to prevent skin abrasion during usage of the face mask assembly. Preferably, the means for absorbing fluids comprises a desiccant, such as silica gel. Ideally, the desiccant is configured to capture condensation locatable within the internal volume defined between the mask body and the wearer. Ideally, the desiccant is configured to capture condensation formed from exhalation. Ideally, the desiccant is configured to capture condensation formed from exhalation, said condensation being locatable within the internal volume defined between the mask body and the wearer. Ideally, the means for absorbing fluids comprises an adhesive dressing. Ideally, the adhesive dressing comprises a hydrocolloid dressing. Ideally, the adhesive dressing is configured to capture moisture and / or oil. In use, the adhesive dressing is configurable to prevent or reduce contact between the elastic seal and the skin of the user. Advantageously, this prevents moisture and oil from accumulating and prevents slippage of the face mask assembly, and in particular the elastic seal. Ideally, the adhesive dressing may be gridded radially and angularly. Ideally, the adhesive dressing is cuttable. Ideally, the adhesive dressing is rollable. Ideally, the adhesive dressing is cuttable according to the shape of the nose-mouth region of the user. Advantageously, the gridding of the adhesive dressing acts as a guide for a user of the face mask assembly for cutting to the shape of the nose-mouth region of the wearer. Ideally, the adhesive dressing is rollable into a truncated cone configuration. Ideally, the mask body comprises a filter means and a mask frame. Ideally, the mask body comprises a mask frame. In another embodiment, the mask body comprises the filter means. In one embodiment, the mask body is detachably connectable to the elastic seal. In preferred embodiments, the mask body is securable to or within the elastic seal. Ideally, in an arrangement, the mask body comprises a mask body framing member configured to secure and / or hold the mask body. Ideally, the mask body framing member forms a rim around the mask body. In an advantageous arrangement, the face mask assembly, and in particular the elastic seal, and even more specifically, the outer tubular member of the elastic seal comprises an expandable seal for securing at least part of or all of the mask body and / or means for adsorbing chemicals and / or biological agents. Ideally, the expandable seal is integrally formed with the elastic seal. Ideally, the expandable seal is homogeneously formed from the elastic seal. Ideally, the expandable seal is integrally formed with the mask base. Ideally, the expandable seal is homogeneously formed from the mask base. Ideally, the expandable seal is locatable at or in the mask base. Ideally, the expandable seal comprises a recess configured to receive at least part of or all of the mask body and / or means for adsorbing chemicals and / or biological agents. Preferably, the expandable seal is reversibly expandable between a rest state and an expanded state. Preferably, the expandable seal is expandable from the rest state to the expanded state by a force (e.g. by stretching). Preferably, the expandable seal is reversibly expandable from the rest state to the expanded state by force. Ideally, the expandable seal contracts upon removal of the force. Ideally, the expandable seal relaxes upon removal of the force. Preferably, the expandable seal is elastically deformable. Ideally, in the rest state, the recess configured to receive at least part of or all of the mask body and / or means for adsorbing chemicals and / or biological agents has an internal volume. Preferably, in the expanded state, the recess configured to receive at least part of or all of the mask body and / or means for adsorbing chemicals and / or biological agents has an internal volume that is larger than the internal volume of said recess within the rest state. Ideally, the mask body and / or means for adsorbing chemicals and / or biological agents is securable to or within the expandable seal. Ideally, the mask body and / or means for adsorbing chemicals and / or biological agents is detachably securable to or within the expandable seal. Ideally, the expandable seal is configured to secure the mask body by expanding the expandable seal to the expanded state, inserting a part of or all of the mask body and / or means for adsorbing chemicals and / or biological agents, and contracting said expandable seal such that it seals around or against the mask body and / or means for adsorbing chemicals and / or biological agents. Ideally, the expandable seal is configured to secure the mask body and / or means for adsorbing chemicals and / or biological agents by expanding the expandable seal to the expanded state, inserting a part of or all of the mask body and / or means for adsorbing chemicals and / or biological agents, and removing the force such that the expandable seal urges towards the rest state such that it seals around the inserted part of or all of the mask body and / or the inserted means for adsorbing chemicals and / or biological agents. Ideally, the mask frame is securable to or within the elastic seal. Ideally, the filter means may be detachably connected to the elastic seal and / or mask frame by use of a fixing means. Preferably, the fixing means may be any suitable means to secure the filter means in use to the elastic seal and / or mask frame. In one example, the filter means may be securable between the mask frame and the elastic seal using the fixing means. Ideally, the elastic seal is formable from an elastic material such as natural or synthetic rubber or silicone. When the face mask assembly is worn, an internal volume is defined between the mask body and the wearer. Ideally, the elastic seal is formable from silicone flexible enough to collapse under the negative pressure created by an adult breathing at rest. Advantageously, this means that the internal volume between the user’s respiratory tract and the mask body is greatly reduced and effectively vented compared to any non-collapsing mask, thereby diminishing the risk of carbon dioxide retention and narcosis. Ideally, the elasticity of the elastic seal is adjustable. The elasticity of the elastic seal may be adjustable by manufacturing the elastic seal from different grades of elastic material and / or by varying the thickness of the elastic seal. Ideally, the face mask assembly is configurable to filter air by electrostatic attraction. More specifically, the elastic seal, and even more specifically, the mask base is configurable to filter air by electrostatic attraction. Ideally, the face mask assembly is deformable. Ideally, the elastic seal is deformable. Ideally, the mask base is deformable. In use, deformation of the face mask assembly causes the face mask assembly to become electrostatically charged or more electrostatically charged. In use, deformation of the elastic seal causes the elastic seal to become electrostatically charged or more electrostatically charged. By more electrostatically charged, we mean that the electrostatic potential of the face mask assembly, and in particular, the elastic seal is greater than the electrostatic potential of said face mask assembly, and in particular the electrostatic potential of the elastic seal prior to deformation. In use, deformation of the elastic seal causes a surface of the elastic seal to become electrostatically charged or more electrostatically charged. By more electrostatically charged, we mean that the electrostatic potential of the surface of the elastic seal is greater than the electrostatic potential of said surface prior to deformation and is therefore configured to exert a greater electrostatic force. We also mean that the electrostatic potential measured on the surface of the elastic seal is greater than the electrostatic potential measured on said surface prior to deformation. In use, elastic deformation of the elastic seal causes the surface of the elastic seal to become electrostatically charged or more electrostatically charged. By more electrostatically charged, we mean that the electrostatic potential of the surface of the elastic seal is greater than the electrostatic potential of said surface prior to elastic deformation and is therefore configured to exert a greater electrostatic force. We also mean that the electrostatic potential measured on said surface of the elastic seal is greater than the electrostatic potential measured on said surface prior to elastic deformation. Ideally, the face mask assembly is rechargeable. Ideally, the elastic seal is rechargeable. Ideally, the mask base is rechargeable. Ideally, the surface of the face mask assembly is rechargeable. Ideally, the surface of the elastic seal is rechargeable. By rechargeable, we mean that the face mask assembly, and in particular the elastic seal is configured to be recharged with electrostatic charges. Advantageously, recharging of the elastic seal also means that the electrostatic potential of the elastic seal is greater, such that face mask assembly, and in particular, the elastic seal is configured to exert a greater electrostatic force to electrostatically trap elements such as microbes and particulates such as dusts and pollens. Preferably, the face mask assembly and more particularly, the elastic seal is rechargeable by deformation of the elastic seal. Preferably, the mask base is rechargeable by deformation of the mask base. Ideally, the surface of the face mask assembly is rechargeable by deformation of the surface of the face mask assembly. Ideally, the surface of the elastic seal is rechargeable by deformation of the surface of the elastic seal. Preferably, the elastic seal is rechargeable by elastic deformation of the elastic seal. Preferably, the mask base is rechargeable by elastic deformation of the mask base. Ideally, the surface of the elastic seal is rechargeable by elastic deformation of the surface of the surface of the elastic seal. Ideally, the face mask assembly is rechargeable by repeated elastic deformation of the face mask assembly, and in particular, repeated elastic deformation of the elastic seal. Ideally, the elastic seal is rechargeable by repeated elastic deformation of the elastic seal. Ideally, the surface of the elastic seal is rechargeable by repeated elastic deformation of the surface of the elastic seal. Ideally, the face mask assembly and in particular the elastic seal is rechargeable by stretching and / or relaxation of the elastic seal. Preferably, the mask base is rechargeable by stretching and / or relaxation of the mask base. Ideally, the surface of the elastic seal is rechargeable by stretching and / or relaxation of the surface of the elastic seal. Ideally, the face mask assembly and in particular the elastic seal is rechargeable by repeated stretching and / or relaxation of the elastic seal. Ideally, the surface of the face mask assembly, and in particular the surface of the elastic seal is rechargeable by repeated stretching and / or relaxation of the surface of the elastic seal. Ideally, the surface of the elastic seal is rechargeable by repeated stretching and / or relaxation of the surface of the elastic seal. Ideally, the face mask assembly, and more specifically, the elastic seal is configured to maintain an electrostatic charge or become more electrostatically charged as the mask is repeatedly used. Even more specifically, the mask base is configured to maintain an electrostatic charge or become more electrostatically charged as the face mask assembly is repeatedly used. Ideally, the face mask assembly, and more specifically, the elastic seal is rechargeable by a user of the mask assembly. Even more specifically, the mask base is rechargeable by a user of the mask assembly. Yet even more specifically, the surface of the elastic seal is rechargeable by a user of the face mask assembly. Ideally, the face mask assembly, and more specifically, the elastic seal is rechargeable during usage of the face mask assembly by a user of the mask assembly. Even more specifically, the mask base is rechargeable during usage of the face mask assembly by a user of the mask assembly. Yet even more specifically, the surface of the elastic seal is rechargeable during usage of the face mask assembly by a user of the mask assembly. Advantageously, this enables the face mask assembly, and in particular the elastic seal to be reusable, as the elastic seal is configured to maintain an electrostatic charge or become more electrostatically charged as the mask is repeatedly used. Ideally, the face mask assembly, and in particular the elastic seal comprises means for filtering inhaled and / or exhaled air by electrostatic attraction. Even more specifically, the mask base comprises the means for filtering inhaled and / or exhaled air by electrostatic attraction. Ideally, the means for filtering inhaled and / or exhaled air by electrostatic attraction is formable from silicone or natural rubber or synthetic rubber. Ideally, the means for filtering inhaled and / or exhaled air by electrostatic attraction is deformable. Preferably, the means for filtering inhaled and / or exhaled air by electrostatic attraction is configured to become electrostatically charged or more electrostatically charged during deformation of the means for filtering inhaled and / or exhaled air by electrostatic attraction. Preferably, the means for filtering inhaled and / or exhaled air by electrostatic attraction is configured to become electrostatically charged or more electrostatically charged by elastic deformation of the means for filtering inhaled and / or exhaled air by electrostatic attraction. Preferably, the means for filtering inhaled and / or exhaled air by electrostatic attraction is configured to become electrostatically charged or more electrostatically charged by repeated elastic deformation of the means for filtering inhaled and / or exhaled air by electrostatic attraction. Ideally, the means for filtering inhaled and / or exhaled air by electrostatic attraction comprises a plurality of pores. Ideally, the plurality of pores is configured to enable passage of inhaled air from the environment and exhalation of air from the wearer. Ideally, the face mask assembly, and in particular the elastic seal comprises a plurality of pores. Even more specifically, the mask base comprises the plurality of pores. Ideally, the plurality of pores has an adjustable cross-sectional area. Ideally, at least one pore of the plurality of pores has an adjustable cross-sectional area. Ideally, the plurality of pores has a non-linear cross- sectional area across the length of the plurality of pores. Ideally, at least one pore of the plurality of pores has a non-linear cross-sectional area across the length of the at least one pore of the plurality of pores. Ideally, the cross-sectional area of the plurality of pores is adjustable in a parallel direction to the direction of the airstream. The airstream may include incoming air inhaled by the wearer of the face mask assembly, or exhaled air that is exhaled by the wearer of the face mask assembly. Ideally, the cross-sectional area of at least one pore of the plurality of pores is adjustable in a parallel direction to the airstream. Advantageously, the adjustable cross-sectional area increases the surface area of silicone an airstream must pass through, thereby maximising electrostatic capture. Ideally, the plurality of pores is formable from a plurality of porous layers. Ideally, the plurality of pores is configured to enable passage of inhaled air from the environment and exhalation of air from the wearer of the face mask assembly. Ideally, each porous layer comprises a plurality of air channels. Ideally, the plurality of air channels of one porous layer interconnect with the plurality of air channels of an adjacent porous layer or adjacent porous layers to form the plurality of pores. Ideally, the plurality of air channels of one porous layer overlaps with the plurality of air channels of an adjacent porous layer or adjacent porous layers to form the plurality of pores. Ideally, the plurality of air channels of one porous layer are in fluid communication with the plurality of air channels of an adjacent porous layer or adjacent porous layers. Ideally, the plurality of air channels of one porous layer are in fluid communication with the plurality of air channels of an adjacent porous layer or adjacent porous layers to form the plurality of pores. Ideally, the plurality of air channels of one porous layer comprises a first cross-sectional area, and the plurality of the air channels of an adjacent porous layer or adjacent porous layers comprise a second cross-sectional area, wherein the first cross-sectional and second cross- sectional area are different to each other. Advantageously, this provides the plurality of pores with an adjustable cross-sectional area in the airflow direction. Ideally, in use, the face mask assembly, and more specifically, elastic seal is configured to electrostatically capture elements such as microbes and particulates such as dusts and pollens. Even more specifically, the mask base is configured to electrostatically capture elements such as microbes and particulates such as dusts and pollens. Yet even more specifically, the surface of the elastic seal is configured to electrostatically capture elements such as microbes and particulates such as dusts and pollens. Yet even more specifically, the plurality of pores is configured to electrostatically capture elements such as microbes and particulates such as dusts and pollens. Ideally, in use, the face mask assembly, and more specifically, elastic seal is configured to electrostatically capture elements such as microbes and particulates such as dusts and pollens exhaled by the wearer and inhaled by the wearer. Even more specifically, in use, the mask base is configured to electrostatically capture elements such as microbes and particulates such as dusts and pollens exhaled by the wearer and inhaled by the wearer. Yet even more specifically, the surface of the elastic seal is configured to electrostatically capture elements such as microbes and particulates such as dusts and pollens exhaled by the wearer and inhaled by the wearer. Ideally, the plurality of pores is configured to electrostatically capture elements such as microbes and particulates such as dusts and pollens exhaled by the wearer and inhaled by the wearer. Preferably, the mask base is deformable. Ideally, the plurality of pores is deformable. Preferably, the plurality of pores is configured to become electrostatically charged or more electrostatically charged during deformation of the plurality of pores. Preferably, the plurality of pores is configured to become electrostatically charged or more electrostatically charged by elastic deformation of the plurality of pores. Preferably, the plurality of pores is configured to become electrostatically charged or more electrostatically charged by repeated elastic deformation of the plurality of pores. Ideally, the plurality of pores is locatable within or on the elastic seal, and more specifically the mask base of the elastic seal. Ideally, the plurality of pores is locatable within a part of or on a part of the elastic seal, and more specifically the mask base of the elastic seal. Ideally, the plurality of pores is integrally formed with the elastic seal, and in particular the mask base. Ideally, the plurality of pores is homogeneously formed from the elastic seal, and particularly the mask base. Advantageously, the plurality of pores reduces the weight of the elastic seal and thus the face mask assembly. This lessens the strain on the wearer of the face mask assembly. Further advantageously, the plurality of pores aids deformation of the elastic seal and thus recharging of the elastic seal. Ideally, said elastic seal is cleanable. Preferably, the plurality of pores is cleanable. Ideally, said elastic seal is cleanable by washing the elastic seal. More specifically, the elastic seal is cleanable by washing the elastic seal to remove any electrostatically attracted matter and / or to sterilise the elastic seal. Ideally, the elastic seal may be washed using any suitable washing fluid, such as a fluid comprising water and / or soap and / or alcohol to remove any electrostatically attracted matter and / or to sterilise the elastic seal. Ideally, the filter means is formable from a porous material that is suitable to act as a filter. Air may be inhaled and exhaled by the wearer through the porous material of the mask body. Ideally, the filter means is arranged to trap elements such as microbes and particulates such as dusts and pollens while allowing air exchange with the external environment. Any porous material such as a porous fabric can be used to make the filter means. For some advantageous arrangements, the filter means comprises polytetrafluoroethylene (PTFE) and in particular expanded or sintered PTFE or a structurally reinforced composite material based on porous PTFE. Using PTFE or a composite therefore allows the filter means to be cleaned at a molecular level through capillary action with perfluorocarbons. This allows the filter means to be reconditioned and reused. In one example, the filter means is formed from a porous PTFE material that is sandwiched between two protective mesh layers. In another example, the filter means comprises a filter pouch formable by at least two or more layers of the porous material. The two of more layers define at least one cavity therebetween. Ideally, the filter means is pleatable. By pleatable, we mean the filter means is capable of being pleated. Preferably, the filter means comprises a pleated sheet. Preferably, the filter means comprises a fully pleated sheet. Ideally, the filter means is pleatable to form a pleated filter means. Ideally, the filter means is pleatable by folding to form a pleated filter means. Ideally, the filter means is pleatable by folding to form a fully pleated filter means. Ideally, the filter means is pleated by folding of the filter means. Advantageously, pleating of the filter means increases the surface area of the filter means available for filtration without increasing the mask volume. This means that the filter means provides a lower airflow resistance. Breathing is easier for the wearer as there is lower airflow resistance and hence lower inspiratory pressure is required. Moreover, the breathing is more energy efficient as there is less dead space to ventilate for the wearer. Yet further advantageously, the filter means being pleatable means that the number of pleats and / or heights of the pleats is customisable to suit different filtration and / or ventilation requirements. Preferably, the filter means may comprise a supporting layer. Preferably, the filter means is laminated with the supporting layer. Advantageously, the supporting layer aids handling of the filter means. Ideally, the supporting layer comprises a non-woven fabric such as spun bound polypropylene or polyethylene terephthalate. Ideally, the filter means comprises a membrane filter. Preferably, the membrane filter is pleated. Ideally, the membrane is pleated to form a pleated membrane. Ideally, the membrane is pleated to form a fully pleated membrane. Ideally, the membrane is pleated by folding of the membrane to form a pleated membrane. Ideally, the membrane is pleated by folding of the membrane to form a fully pleated membrane. Advantageously, the pleating of the filter means, and more specifically, the membrane reduces the effective pore size exposed to particles carried by convection in the airflow. This means that pore sizes larger than the diameter of the smallest particles required to be trapped may be used whilst also maintaining high filtration efficiency. Further advantageously, this reduces the airflow resistance whilst also maintaining high filtration efficiency. Ideally, the filter means is cleanable. Preferably, the filter means is cleanable such that the filter means may be re-used. Ideally, the filter means if cleanable and re-useable. Ideally, the filter means is cleanable using a fluid configured to wet the filter means. By wet the filter means, we mean that said fluid configured to wet the filter means is configured to adhere to and is able to penetrate the filter means upon contact with the filter means. In one embodiment, said fluid configured to wet the filter means comprises an alcohol, such as isopropanol. In an advantageous arrangement, wherein the filter means comprises expanded PTFE and is formed from a membrane filter, said filter means is cleanable by rubbing or washing the filter with a jet using a fluid configured to wet the filter means. Advantageously, the cleaning of the filter means in such a manner dislodges fine particles embedded in filter means from usage of the face mask assembly. In this advantageous arrangement, the fluid configured to wet the filter means may comprise an alcohol, such as isopropanol. Ideally, where the filter means comprises a pleated sheet, the number of pleats and / or height of the pleats of the pleated sheet is adjustable. Advantageously, this adjustability enables the same filter means to be configurable to be adapted to different filtration requirements. Ideally, the face mask assembly, and more particularly, the mask body, and even more particularly, the filter means comprises a means for adsorbing chemicals and / or biological agents. Ideally, the filter means may be impregnated with the means for adsorbing chemicals and / or biological agents. In one example, the filter means is impregnated during the formation of the filter means. In another example, where the filter means comprises a filter pouch, the means for adsorbing chemicals and / or biological agents is locatable in the at least one cavity therebetween. In yet another example, the means for adsorbing chemicals and / or biological agents is a separate to, and works in conjunction with, the filter means to filter air. In this example, the means for adsorbing chemicals and / or biological agents may comprise at least one layer of a means for adsorbing chemicals and / or biological agents. Ideally, the means for adsorbing chemicals and / or biological agents may be disposed between the mask base and the mask body. Ideally, the means for adsorbing chemicals and / or biological agents may be disposed between the mask base and the filter means. Ideally, the means for adsorbing chemicals and / or biological agents may comprise any suitable material configured for adsorbing chemicals and / or biological agents such as activated charcoal or copper for adsorption of noxious chemicals and / or for killing of microbes. Preferably said means for adsorbing chemicals and / or biological agents is configured to adsorb water vapour exhaled by the wearer. Advantageously, this reduces the build-up of moisture during usage of the face mask assembly, and in particular the elastic seal. In one arrangement, wherein the means for adsorbing chemicals and / or biological agents comprises activated charcoal, said means for adsorbing chemicals and / or biological agents may be formable from a biodegradable material, such as coconut husks subjected to carbonisation for example. Ideally, the face mask assembly may be a gas mask for industrial use and / or for use against chemical weapons and / or for use against biological agents. In this embodiment the face mask assembly covers the entire face of the wearer thereby covering the wearer’s eyes. In this embodiment the seal covers the entire face of the wearer thereby covering the wearer’s eyes. Means are provided for allowing a wearer to see through a face mask of the type which covers the entire face of the wearer. Transparent portions are provided in a corresponding location of the mask to the eyes of a wearer for allowing a wearer to see through a face mask of the type which covers the entire face of the wearer. Ideally, the face mask assembly is adaptable to form an airtight fit around different nose- mouth contours. Ideally, the face mask assembly may further comprise a harness arranged to support the elastic seal on the object. Preferably, the harness may be coupled to the elastic seal. The harness may be coupled directly and / or indirectly to the elastic seal. Preferably, the harness may be coupled to the mask body. Preferably, the harness may be coupled directly and / or indirectly to the mask body. Preferably, the harness may be coupled directly and / or indirectly to a mask body that is integrated into the elastic seal to support the elastic seal on the object. Ideally, the harness may comprise one or more straps. In some embodiments, the or each strap may be a single-layered strap. In some embodiments, the, or each, strap may comprise a plurality of strap layers. Ideally, one or more straps may comprise a first strap and a second strap. Optionally, the first strap may be interconnected to the second strap by an interconnecting strap. Each strap is securable directly and / or indirectly to the elastic seal and / or mask body via one or more attachment means. In some arrangements, the one or more attachment means may form part of the mask body integrated into the elastic seal. That is, the mask body may comprise one or more attachment means arranged for the securement of one or more straps of a harness thereto. Each strap is securable directly and / or indirectly to one or more attachment means forming part of the mask body integrated into the elastic seal. In other arrangements, the attachment means need not form part of the mask body and may instead be separate to the mask body. In these arrangements, the one or more attachment means may be integrated into the elastic seal (e.g. through overmoulding for example). The one or more attachment means may be located within and / or on a surface of the outer tubular member and / or the mask base. The harness may be securable directly and / or indirectly to the one or more attachment means to compressively secure the elastic seal to the face of the wearer of the face mask assembly. Each strap may be securable indirectly to one or more attachment means via an intermediary coupling member, said strap being securable directly to the intermediary coupling member. Each strap may be securable directly and / or indirectly to the elastic seal and / or one or more attachment means via at least one securing means for securing the harness to the elastic seal and / or mask body. Ideally, each strap is adjustable so as to control the force with which the elastic seal is pulled onto the face of a user of the face mask assembly. Each strap may be adjustable so as to control the force with which the elastic seal is pulled onto the face of a user via adjustment of the at least one securing means. Accordingly, the, or each, securing means is operable to adjust the force with which the elastic seal is pulled onto the face of a user of the face mask assembly. The, or each, securing means may comprise a securing loop formable from use of at least one fastener. The fastener may comprise a hook-and-loop fastener. The hook-and-loop fastener may comprise a hook-and-loop fastening layer. The hook-and-loop fastening layer may form at least one layer of the plurality of strap layers and accordingly, this layer may also be referred to as the securing layer. Alternatively, in embodiments where each strap is a single-layered strap, the single-layered strap may be the securing layer. In more detail, the securing layer comprises a first securing layer surface, one or more hooking means and a second securing layer surface. The first securing layer surface comprises a loop portion located on at least part of, or all of, the first securing layer surface. The second securing layer surface may be a non-loop layer surface. By non-loop layer surface, it will be understood that this surface does not comprise loops for engaging with the hooking means. Each strap may comprise a first hooking means located at a first end of the strap, and a second hooking means located at a second end of the strap, said second end being distal to the first end of the strap. The, or each, hooking means may comprise a hooking patch for fastening to the loop portion of the first securing layer surface. The hooking patch may comprise a first hooking surface for fastening to the loop portion, and a second hooking surface for fastening to the loop portion. The hooking patch is fastenable, and more preferably, detachably fastenable to a first part of the loop portion via the first hooking surface. The fastened hooking patch that is fastened on the first part of the loop portion is fastenable, and more preferably, detachably fastenable to a second part of the loop portion, via the second hooking surface so as to form the securing loop. Beneficially, the ability to detachably fasten the hooking patch enables a user of the face mask assembly to control the force with which the elastic seal is pulled onto an object, such as the face of a wearer of the face mask assembly. In embodiments where the strap comprises a plurality of layers, the strap may comprise a backing layer. The backing layer may comprise a first backing layer surface and a second backing layer surface. The backing layer may be an inelastic layer. The backing layer may be a flexible layer. The backing layer, and in particular, the first backing layer surface is configured to engage with the second layer of the securing layer. Beneficially, where the backing layer is inelastic and flexible, the backing layer is configured to prevent narrowing and twisting of the strap so as to prevent a twisted strap abrasively rubbing against the face of a user of the face mask assembly. In embodiments where the strap comprises a plurality of strap layers, the strap may comprise an elastic strap layer. The elastic strap layer may be formed from silicone and may be referred to as a silicone strap layer. The silicone strap layer is functionable as a non-slip strap layer. Beneficially, the usage of a silicone, when in contact with skin, results in a high coefficient of friction, thereby enabling the silicone strap layer to function as a non-slip layer in use. The elastic strap layer is configured, in use, to stretch in a transverse and longitudinal direction. The elastic strap layer is an auxetic strap layer and / or demonstrates quasi-auxetic behaviour. Beneficially, the elastic strap layer is arranged to spread the normal force that is generated in response to tension generated in the strap so as to increase the area of contact with the skin of the user of the face mask assembly, thereby reducing the pressure exerted which mitigates any risk of discomfort and skin damage during usage of the face mask assembly. In an embodiment, the elastic seal may comprise at least one recess sized to accommodate part of the mask body. In an embodiment, the mask frame comprises a three-dimensional shell comprising a top panel, and a plurality of side panels extending from the top panel. In another embodiment, the mask frame comprises a pleated frame. Preferably, the pleated frame is a fully pleated frame. Preferably, the mask frame is configurable to provide structural support and flexibility to the mask body. Ideally, the mask frame is formable from a material configured to provide structural support and flexibility. The material configured to provide structural support and flexibility may also be known as a semi-rigid material. Advantageously, the use of a material configured to provide structural support and flexibility enables the mask frame to retain the shape of the three-dimensional shell or pleated frame whilst also enabling the frame to adapt to shape changes in the user’s face during usage of the face mask assembly. Ideally, the mask frame may be formed from material configured to provide structural support and flexibility such as mylar. Ideally, the face mask assembly is functionable as a CPAP face mask assembly. The face mask assembly may be useable for non-invasive and minimally invasive ventilation applications. The face mask assembly may be connectible to a CPAP machine. The elastic seal, and in particular the mask base of the elastic seal and / or the mask body may be connectible to a CPAP machine. The face mask assembly may also be connectible to a mechanical ventilation system for mechanical ventilation of the lungs. The mask body may comprise a mask frame that is integrally formed with the elastic seal, and more preferably integrally formed with the mask base of the elastic seal. The mask body may be integrated into the mask base of the elastic seal. The mask frame of the mask body may be integrated into the elastic seal. Ideally, the face mask assembly may be configured to maintain an airtight seal around the nose and mouth of the wearer at a positive pressure of at least 5 cmH2O. The face mask assembly may be configured to maintain an airtight seal around the nose and mouth of the wearer at a positive pressure of at least 10 cm H2O.The face mask assembly may be configured to maintain an airtight seal around the nose and mouth of the wearer at a positive pressure of at least 15 cmH2O. The face mask assembly may be configured to maintain an airtight seal around the nose and mouth of the wearer at a positive pressure of at least 20 cmH2O. The mask frame may comprise at least one ring-shaped portion. The at least one ring- shaped portion may comprise a single ring-shaped portion or a plurality of ring-shaped portions. At least one, or each, ring-shaped portion may be circular or non-circular (e.g. polygonal, oval) in shape. At least one, or each, ring-shaped portion may define a respective mask frame aperture therein. The at least one ring-shaped portion includes a ring-shaped portion that is arranged, in use, to support the securement of a connecting means (e.g. a vent ring) for connecting the face mask assembly to a CPAP machine. In some arrangements, the at least one ring-shaped portion may be arranged to secure the connecting means for connecting the face mask assembly to a CPAP machine. In embodiments where the mask frame comprises a single ring-shaped portion, said mask frame portion may define the mask frame aperture arranged, in use, to support the securement, within the mask base aperture, of a connecting means (e.g. a vent ring) for connecting the face mask assembly to a CPAP machine. In preferred embodiments, the at least one ring-shaped portion, and more particularly, the plurality of ring-shaped portions may comprise a first ring-shaped portion and a second ring portion bridged to the first ring-shaped portion via one or more bridging members. The first ring- shaped portion may therefore define a first mask frame aperture. The second-ring shaped portion second may define a second mask frame aperture. The first ring-shaped portion and the second ring-shaped portion are concentrically arranged with respect to each other. In these arrangements where the first ring-shaped portion is, preferably, an innermost ring-shaped portion and the second ring-shaped portion may be an outermost ring-shaped portion. Alternatively, the second ring-shaped portion can be an outer ring- shaped portion, such as, for example, an intermediate ring portion disposed between the innermost ring-shaped portion and one or more ring-shaped portions. The innermost ring portion is, preferably, the ring-shaped portion that is arranged in use to support the securement, within the mask base aperture, of a connecting means (e.g. a vent ring) for connecting the face mask assembly to a CPAP machine. Beneficially, the inclusion of a first ring-shaped portion and a second ring-shaped portion bridged to the said first-ring shaped portion improves structural strength and prevents blow-out of the mask base during usage of the face mask assembly when air pressure is high, such as when the face mask assembly is used during CPAP therapy. In embodiments where the mask frame comprises an innermost ring-shaped portion and an outermost ring-shaped portion, the one or more attachment means may extend from the outermost ring-shaped portion. The face mask assembly may be connectible to a CPAP machine. The mask base may comprise a mask base aperture for securing objects therein and / or thereto. In embodiments where the face mask assembly is used as a face CPAP face mask assembly, the mask base aperture may be arranged to secure a connecting means, such as a vent ring, for connecting a CPAP machine to the face mask assembly. The vent ring may comprise tubing attached to the vent ring. The mask body, and particularly the mask frame, comprises a mask frame aperture. The mask frame aperture may have a diameter greater than the diameter of the mask base aperture. The mask body, and more preferably, the mask frame may be arranged to support the securement of the connecting means for connecting the face mask assembly to a CPAP machine within the mask base aperture. The mask body may comprise one or more attachment means extending from the mask frame. In some embodiments, where the mask body comprises a mask frame that is integrated into the mask base of the elastic seal, the, or each, attachment means may extend through the elastic seal. In these embodiments, the, or each, attachment means may extend through a corresponding slit formed within the mask base for protrusion of the attachment means therethrough. In other embodiments, the mask body may be separate from and securable within and / or to the elastic seal. In these embodiments, the mask body may be arranged to directly secure the connecting means for connecting a CPAP machine to the face mask assembly. The, or each, attachment means is configured for a harness to be coupled directly and / or indirectly thereto. The, or each, attachment means may comprise one or more attachment loops. Beneficially, in embodiments wherein the, or each, each strap of the harness is coupled directly and / or indirectly to one or more attachment loops, each loop is rotatable, in use, about a first orthogonal axis, said first orthogonal axis being the longitudinal axis of the attachment loop, a second orthogonal axis and a third orthogonal axis, wherein rotation about the first orthogonal axis provides each strap directly and / or indirectly coupled to a respective attachment loop with an additional torsional component to the tangential pull exerted by the, or each, strap. This enables the face mask assembly to accommodate different head pull directions associated with user’s having different head shapes and sizes. The face mask assembly may comprise one or more intermediary coupling members for indirectly coupling the harness to the elastic seal and / or mask body. The harness may be indirectly coupled to one or more attachment means of the mask body via the one or more intermediary coupling members. The one or more intermediary coupling members may comprise one or more coupling loops, such as circular loops. The one or more intermediary coupling members are configured to enable angular adjustment of the harness in use. In particular, in embodiments wherein each strap comprises a securing means that is operable, in use, to form a securing loop, the securing loop may be securable to a respective coupling loop and is slidable about the respective loop. Beneficially, this provides the face mask assembly with the ability to accommodate different three-dimensional shapes associated with users of the face mask assembly. Advantageously, the mask frame may be formable from a single folded sheet of material configured to provide structural support and flexibility without any joints formed by welding, sewing, adhesives, or other attachment methods. Ideally, a single sheet of material may be folded to form the mask frame. This simplifies the construction of the mask frame as separate elements are not required to be attached together to form the mask frame. The absence of joints that require attachment reduces the risk of leakage and simplifies the manufacturing process. Ideally, the mask body is pleated. Ideally, at least part of or all of the mask body is pleated. Ideally, at least part of or all of the mask frame and / or at least part of or all of the filter means is pleated. Ideally, the mask frame and / or the filter means is fully pleated. By fully pleated, we mean that the mask frame and / or the filter means is pleated across the entire length and entire width of the mask frame and / or the filter means. In one embodiment, the pleated mask frame and the pleated filter means are configured to engage with each other. Ideally, where the mask frame is fully pleated, and the filter means is fully pleated, the fully pleated filter means and the fully pleated mask frame are configured to engage with each other. In an advantageous arrangement, the pleated mask frame is secured to the pleated filter means using the fixing means. In this arrangement, the fixing means ties the pleated filter means and pleated mask frame together using at least one tie. In this arrangement, the fixing means is received by a plurality of mask frame apertures configured to receive the at least one tie and a plurality of filter means apertures configured to receive the at least one tie. Ideally, the pleated mask body may comprise adjusting means configured to loosen and / or tighten the pleated mask body. By loosen the pleated mask body, we mean that the pleats of the mask body are slackened via use of the adjusting means. By tighten, we mean that the pleated mask body is tauter and more compressed via use of the adjusting means. Ideally, the adjusting means comprises an elastic means configured to loosen and / or tighten the pleated mask body. Ideally, the elastic means may comprise an elastic band connectible to the at least one tie. Ideally, the mask frame comprises at least one pleat. In one embodiment, the top panel may comprise the at least one pleat. Ideally, the at least one pleat may be formed by folding the material of the mask frame. Advantageously, the at least one pleat increases the surface area of the mask frame available for filtration without increasing the mask volume. This means that the mask frame provides a lower airflow resistance. Breathing is easier for the wearer as there is lower airflow resistance and hence lower inspiratory pressure is required. Moreover, the breathing is more energy efficient as there is less dead space to ventilate for the wearer. Advantageously still, the at least one pleat provides additional rigidity to the mask frame which means that the mask frame is less likely to collapse and wrap around the wearer’s nose and mouth during inhalation. Ideally, the at least one pleat provides additional rigidity without increasing the bulk and weight of the mask frame. Advantageously still, the at least one pleat enables the mask frame to increase in size when the wearer opens their mouth. This helps prevent the mask frame from slipping off the wearer’s face. Advantageously still, the at least one pleat can function as a bellow when actuated by the jaw muscles of the wearer to refresh the air in the mask, aid the wearer’s breathing, or force out water vapour that may otherwise condense into droplets within the mask. This bellow function can be intentionally activated by the wearer or may occur coincidentally such as when the wearer speaks. Ideally, the at least one pleat may comprise a plurality of pleats. In one embodiment, the plurality of pleats may be arranged parallel to one another along the top panel. In another embodiment, the plurality of pleats forms the pleated frame. In this embodiment, the pleated frame may be a fully pleated mask frame. Ideally, the pleated frame, and more specifically, the fully pleated mask frame is formable by folding the mask frame along fold-lines. Ideally, the mask frame may comprise at least one aperture. Preferably, the at least one aperture is locatable on the top panel and / or the plurality of side panels. In another embodiment, the at least one aperture is locatable on the plurality of pleats. Ideally, the at least one aperture is locatable on the at least one pleat, and preferably, on each pleat of the plurality of pleats. Ideally, the at least one aperture is locatable on the pleated frame. Advantageously, the at least one aperture is configurable to enable the user to breathe easier by lowering the airflow resistance. In a preferred embodiment, the at least one aperture comprises a circular shape. Ideally, two of the side panels arranged opposite one another and separated by the top panel may comprise a corresponding at least one pleat. When the top panel comprises a plurality of pleats, the two of the side panels may each comprise a corresponding plurality of pleats. Preferably, the pleats of the side panels may be aligned with the pleats of the top panel. Ideally, the at least one pleat may be formed by folding the mask frame along fold-lines. Ideally, the fold-lines may be stiffened regions of the mask frame. Ideally, the mask frame may further comprise a valve provided between a pair of adjacent side panels. Preferably, the mask frame may comprise a plurality of valves each provided between a pair of adjacent side panels. Ideally, the valve may be formed by folding the mask frame. Preferably, the mask frame may be folded along fold-lines. Ideally, the fold-lines may be stiffened regions of the mask frame. Preferably, the valve may be normally closed and may open in response to air pressure increasing within the mask body. When the valve opens, it may define an air passageway for air to escape from the mask body. The air passageway may face away from the top panel and may be provided towards a lower margin of the side panels. Advantageously, when the pressure increases within the mask body, such as due to the wearer exhaling, the valve opens. The air passageway formed by the valve faces away from the top panel which means that the exhaled air first hits the top panel and / or filter means before bouncing off into the valve for expulsion via the air passageway. Water and mucus droplets and other large particles expelled by the wearer are likely to be deposited on the top panel and / or filter means and only air and gases are expelled to the outside through the valve. Ideally, the valve may project outwardly from the pair of adjacent side panels. Ideally, the valve may be formed by folding the material along three fold-lines to form a pair of facing sides that terminate in an outer-edge. Ideally, the sides may move away from each other in response to the pressure within the mask body increasing. Ideally, the sides may taper towards an upper margin of the side panels. Ideally, the sides may comprise cut-out regions towards a lower margin of the side panels. Ideally, the cut-out regions define an air passageway which opens in response to pressure within the mask body increasing. Preferably, the elastic seal is configurable to be changed between a first configuration and a second configuration, wherein in the second configuration, the elastic seal is adapted to form a sealing perimeter around the mouth and nose of a wearer. The second configuration may therefore be regarded as a deployed configuration. More specifically, the seal is adapted to form a sealing perimeter around a shape comprising a contour comprising convex and concave curvature. Additionally, the elastic seal is configurable to be changed between a first configuration and a second configuration, wherein in the second configuration, the elastic seal is configured to form a sealing perimeter around the mouth and nose and / or eyes of a wearer. Ideally, the first configuration is the rest configuration and the second configuration is the inverted configuration. Ideally, the face mask assembly comprises means for reducing the airflow resistance of inhaled and / or exhaled air. Ideally, the elastic seal and / or the mask body comprises the means for reducing airflow resistance of inhaled and / or exhaled air. Ideally, the means for reducing the airflow resistance of inhaled and / or exhaled air comprises the at least one aperture configurable to enable the user to breathe easier by lowering the airflow resistance. Ideally, the elastic seal comprises a plurality of openings locatable on the mask that are configured to enable the user to breathe easier by lowering the airflow resistance. Ideally, the elastic seal, when donned on the face of a user of the face mask assembly via the inner tubular member in the deployed configuration, is collapsible in height under compression. It will be understood here that height here refers to the distance between the opening defined between the first end of the elastic seal comprising the sealing perimeter and the second end of the elastic seal comprising the mask base. For example, in embodiments where a harness is used to secure, and more particularly, compressively secure the elastic seal to the face of a wearer of the face mask assembly, the elastic seal may be collapsible from a rest state to a compressed state. Accordingly, the elastic seal, when donned on the face of a user of the face mask assembly via the inner tubular member in the deployed configuration, is collapsible to a compressed state, and in particular, is collapsible to the compressed state via usage of a harness. In the compressed state, the inner tubular member may be configured to be packed within, or at least partially encapsulated by the outer tubular member under compression, such as when a harness is used on the elastic seal in a face mask assembly (e.g. in a compressive securement arrangement). In other words, the inner tubular member of the elastic seal, in the deployed configuration, may be packable within or at least partially encapsulatable by the outer tubular member under compression, such as when a harness is used to secure the elastic seal to the face of a wearer of the face mask assembly (e.g. in a compressive securement arrangement). In this way, the outer tubular member may be configured to function as buttress for the inner tubular member in the collapsed state. Advantageously, the inner tubular member being packed within or at least partially encapsulated by the outer tubular member mitigates expansion of the inner tubular member resulting from application of the elastic seal on the face of a user of the face mask assembly, and more preferably resulting from application of the elastic seal on the face of a user of the face mask assembly, said face mask assembly functioning as a CPAP face mask assembly during CPAP therapy. The outer tubular member may be configured to seal around the inner tubular member under a compressive force. In particular, the elastic seal, when donned on the face of a user of the face mask assembly via the inner tubular member in the deployed configuration, is preferably compressible such that the outer tubular member is configured to seal around the inner tubular member. In this way, the outer tubular member being configured to seal around the inner tubular member thereby enables formation of a further (or second) seal around the seal formed between the inner tubular member and the object to which the elastic seal is being applied (e.g. the face of the wearer of a face mask assembly comprising the elastic seal). This further seal may also be referred to as the external seal, and the seal formed between the inner tubular member and the object to which the elastic seal is being applied may be referred to as the internal (or first) seal. Advantageously, the implementation of this external seal helps to buffer against the compressive force exerted on the face of a user of the face mask assembly via application of the harness (e.g. when the harness is in a compressive securement arrangement). It will therefore be understood that the elastic seal may comprise a buffering region to buffer against the compressive force exerted on the face of a user of the face mask assembly via application of the harness to secure, and preferably, compressively secure the elastic seal to the face of the wearer of the face mask assembly. In some arrangements, the outer tubular member may be arranged to seal around the inner tubular member under compression by the outer tubular member splaying outwards as a result of said compression and, preferably, to accommodate the packing or partial encapsulation of the inner tubular member therein. The outer tubular member may be arranged to splay outwards when the elastic seal is under compression, and, preferably, may be configured to accommodate the packing or partially encapsulation of the inner tubular member in the splayed configuration. In this way, additional elastic seal material is packed more tightly in the space between the inner tubular member and the outer tubular member in order to buffer against the compressive force exerted on the face of a user of the face mask assembly through the harness. In other arrangements, the outer tubular member may be configured to seal around the inner tubular member under compression by partially collapsing under compression to create folds in an inward facing surface of the outer tubular member. In other words, the inner tubular member may be configured to be packed within, or at least partially encapsulated by the folds formed in an inward facing surface of the outer tubular member that has partially collapsed to form the external seal around the inner tubular member. In this way, additional elastic seal material is packed around the inner tubular member in order to buffer against the compressive force exerted on the face of a user of the face mask assembly through the harness. In each of the abovementioned arrangements, the elastic seal comprises a buffering region for absorbing at least part of the compression force exerted on the face of a wearer of the face mask assembly via application of the harness. In this way, the face of a user of the face mask assembly may experience less pressure during usage of the face mask assembly because of the absorption of some of the compressive force exerted by the harness on the elastic seal, thereby improving the comfort for a user of such a face mask assembly. In some arrangements, the buffering region may comprise the bridging portion and / or at least part of the inner tubular member of the elastic seal. The at least part of the inner tubular member may comprise the bent portion. In some arrangements, the buffering region may comprise the folds formed in an inward facing surface of the outer tubular member that has partially collapsed to form the external seal around the inner tubular member. Ideally, the elastic seal, when donned on the face of a user of the face mask assembly via the inner tubular member in the deployed configuration, is compressible such that the bent portion of the inner tubular member is packed within and / or at least partially encapsulated by the outer tubular member. In use, this packing of additional seal material between the inner tubular member and outer tubular member assists in buffering against the compressive force exerted on the face of a wearer of the face mask assembly. According to a second aspect of the disclosure, there is provided an elastic seal arranged to form a seal around an object. The elastic seal comprises an inner tubular member, a bridging portion and an outer tubular member. The elastic seal is not limited to forming seals around any particular object. However, in preferred examples, the elastic seal is used as a face mask seal to form a sealing perimeter around the nose and mouth of a wearer. The elastic seal may therefore be used to improve the sealing of face masks. The elastic seal may be provided as part of a face mask. The seal is not limited to use in face mask seals and can also be used to form seals around other objects such as other parts of animal (such as a human) anatomy. In some examples, the seal can be used to form a sealing perimeter around the eyes of the wearer to protect the eyes from contact with water or other toxic or undesirable substances. The elastic seal may comprise any of the features of the elastic seal described above in relation to the first aspect of the disclosure. The elastic seal may be arranged to form a seal around a wearer. The elastic seal may be a face mask seal arranged to form a sealing perimeter around a nose and mouth of the wearer. Advantageously, the present disclosure provides an elastic face mask seal that is able to be stretched to accommodate various facial sizes and shapes. A single size of elastic seal may be utilised for multiple different facial sizes and shapes. It is therefore not required for the wearer to go through fit testing to find the correct face mask seal size. According to a third aspect of the disclosure, there is provided a mask frame comprising a three-dimensional shell comprising a top panel, and a plurality of side panels extending from the top panel, wherein the top panel comprises at least one pleat. The mask frame may comprise any of the features of the mask frame described above in relation to the first aspect of the disclosure. According to a fourth aspect of the disclosure, there is provided a mask frame comprising a pleated frame. The mask frame may comprise any of the features of the pleated mask frame described above in relation to the first aspect of the disclosure. According to a fifth aspect of the disclosure, there is provided a mask body. The mask body may comprise any of the features of the mask body described above in relation to the first aspect of the disclosure. According to a sixth aspect of the disclosure, there is provided a filter means comprising a pleated sheet. The filter means may comprise any of the features of the filter means described above in relation to the first aspect of the disclosure. According to a seventh aspect of the disclosure, there is a method of using a face mask assembly, wherein the method comprises: providing a face mask assembly comprising an elastic seal and a mask body, said elastic seal comprising an inner tubular member, a bridging portion and an outer tubular member; inverting the inner tubular member from a rest configuration to a deployed configuration; and applying the inner tubular member, in the deployed configuration, around the nose and mouth and / or eyes of a wearer of the face mask assembly to form a sealing perimeter around the nose and mouth and / or eyes of the wearer. The face mask assembly may comprise any of the features of the face mask assembly described above in relation to the first aspect of the disclosure. The elastic seal may comprise a mask base. The mask base may comprise a mask base aperture for securing objects therein and / or thereto. The method of using the face mask assembly may further comprise connecting the face mask assembly to a CPAP machine. Connecting the face mask assembly to a CPAP machine may comprise securing a connecting means for connecting a CPAP machine to the face mask assembly. The connecting means may comprise a vent ring. According to an eight aspect of the disclosure, there is provided a continuous positive airway pressure (CPAP) system, the CPAP system comprising: a CPAP machine; and a face mask assembly comprising an elastic seal and a mask body, said elastic seal comprising an inner tubular member, a bridging portion and an outer tubular member. The face mask assembly may comprise any of the features of the face mask assembly described above in relation to the first aspect of the disclosure. The face mask assembly is connectable to the CPAP machine. The elastic seal may comprise a mask base. The face mask assembly may comprise a connecting means for connecting a CPAP machine to the face mask assembly. The connecting means may comprise a vent ring. The CPAP system may further comprise tubing for coupling the connecting means to the CPAP machine. The connecting means, and in particular, the vent ring may be arranged to be secured within a mask base aperture of the mask base of the elastic seal. According to a ninth aspect of the disclosure, there is provided a harness for a face mask assembly. The harness may comprise any of the features of the harness described within the first aspect of the disclosure. According to a tenth aspect of the disclosure, there is provided a face mask assembly comprising an elastic seal, the elastic seal comprising: a first tubular member that is arranged for forming a sealing perimeter around the face of a wearer, a second tubular member, and a bridging portion; wherein the elastic seal is prefabricated such that it has a single stable state configuration, wherein the single stable state configuration is a donning configuration. It will be understood here that the elastic seal of the present aspect of the disclosure is like the elastic seal of the face mask assembly as described in the first aspect of the disclosure. For the elastic seal itself, the first tubular member is like the inner tubular member as described in the first aspect of the disclosure, the bridging portion is like the bridging portion as described in the first aspect of the disclosure and the second tubular member is like the outer tubular member as described in the first aspect of the disclosure. However, in the present aspect of the disclosure, the elastic seal of the face mask assembly has been prefabricated such that it has a single stable state configuration, wherein the single stable state configuration is a donning configuration. In other words, the elastic seal of the face mask assembly is not invertible between a rest configuration, in which the first tubular member is nested within the second tubular member, and an inverted (or deployed) configuration in which the first tubular member is inverted and arranged to form a sealing perimeter around the face of a wearer of the face mask assembly. Advantageously, the prefabrication of the elastic seal in this way ensures that the wearer of the face mask assembly can readily don the mask without having to invert the first tubular member, thereby making it easier and accessible for donning of the mask. Furthermore, by donning configuration, it will be understood that this refers to the elastic seal, in an unworn state, being able to be readily donned on the face of a wearer of the face mask assembly. Ideally the face mask assembly comprises a mask body. The mask body may comprise any of the features as described for the mask body described in the first aspect of the disclosure. Ideally the bridging portion bridges the first tubular member to the second tubular member. Ideally, the elastic seal has a generally hyperboloidal shape. Ideally, the elastic seal is prefabricated to have a generally hyperboloidal shape in an unworn state. Ideally, the inner tubular member has a generally hyperboloidal shape. Ideally, the elastic seal is prefabricated such that the inner tubular member has a generally hyperboloidal shape in an unworn state. Ideally, the first tubular member has a first tubular member length. Ideally, the second tubular member has a second tubular member length. Ideally, the second tubular member length is shorter than the first tubular member length. Ideally, the first tubular member of the elastic seal, in an unworn state, is arranged to extend away from, and is not nested within, the second tubular member. Ideally, the elastic seal is prefabricated such that the first tubular member extends away from, and is not nested within, the second tubular member. Ideally, the first tubular member, in an unworn state, is not invertible from the donning configuration to a nested configuration in which the first tubular member is stably nested within the second tubular member. Ideally, the second tubular member may be partially collapsible. The second tubular member collapsibility may be adjustable. The second tubular member may comprise an inward- facing tubular member surface and an outward-facing tubular member surface. By inward facing, it will be understood that is surface is contactable with air being breathed in and out of the face mask assembly during usage of the face mask assembly. The second tubular member may be partially collapsible in use to create folds in the inward facing surface. Beneficially, the folds increase the surface area of the inward facing surface of the second tubular member so as to increase the condensation of moisture on this surface. In CPAP applications users of CPAP face masks may suffer discomfort from dry mouth and dry nose. In the present disclosure, the increased condensation arising as a result of the folds humidifies the air breathed in by a user of the face mask assembly, thereby mitigating or obviating such discomforts. Furthermore, in CPAP applications, the use of a separate humidifying unit is not necessary, as the trapping of moisture using the folds enables a user to humidify the internal volume of the face mask assembly. Ideally, the second tubular member comprises a control means for adjusting the collapsibility of the second tubular member. Ideally, the control means for controlling the collapsibility of the second tubular member may comprise one or more second tubular member splines. The one or more second tubular member splines may be homogenously formed as part of the second tubular member. The collapsibility of the second tubular member may be adjustable by varying the number of splines and / or stiffness of the splines incorporated into the second tubular member. Optionally, the elastic seal, and in particular, the first tubular member comprises a skirting portion. The skirting portion is locatable on the perimeter that is functionable, in use, to form the sealing perimeter around the face of a user of the face mask assembly. Beneficially, the skirting portion is configured to stop the first tubular member retracting longitudinally when circumferentially stretched in the donning configuration, thereby mitigating the Poisson effect associated with the stretching of such an elastic seal. Yet further beneficially, the skirting portion, in use, is operable to seal around the face of the wearer, such as around the nose-mouth contour and to plug gaps formed between and within pads forming part of the padding means. Yet even further beneficially, the skirting portion is configured to protect the sealing perimeter from tearing in use. The skirting portion may be configured to seal around the face of the user of the face mask assembly in the sagittal plane. Ideally, the elastic seal comprises a mask base. The mask base of the elastic seal may also be referred to as an elastic seal base. The mask base may be located distal to a first end of the elastic seal, said first end comprising a shape-receiving opening for sealing around the face of a wearer of the face mask assembly. The mask base may be located at a second end of the elastic seal. That is, the elastic seal comprises a first elastic seal end and a second elastic seal end. The inner tubular member, bridging portion and outer tubular member may extend between the first end and second end of the elastic seal. The mask base may comprise a mask base aperture. The mask body may be insertable into the mask base aperture. The mask base aperture may be arranged to receive a connecting means for connecting a CPAP machine to the face mask assembly. Ideally, a shape-receiving opening is locatable at an end of the first tubular member. Ideally, the shape-receiving opening is configurable to receive the face of the wearer of the mask. Ideally, the shape-receiving opening is configurable to be flexible and adaptable to the shape being received. The shape-receiving opening may be a first opening. The mask base aperture may be a second opening. Ideally, the first tubular member comprises a bent portion. The bent portion is a concave bent portion. The bent portion is adjacent to the bridging portion of the elastic seal. Advantageously, the recoil of the bend exerts a force to urge the first tubular member to seal around the nose and mouth of the wearer. More specifically the recoil of the bend exerts a force to urge the first tubular member to seal around a shape comprising convex and concave curvature such that the first tubular member thereby forms an effective sealing perimeter around the convex and concave curvature of the shape. Advantageously the elastic seal of the face mask assembly, in use, is configured to provide concentric contraction around and centripetal radial compression across the first tubular member to increase the friction between the elastic seal and face of the user and to prevent the elastic seal from slipping off the face of the user. Ideally, the elastic seal comprises means for preventing slippage of the elastic seal. Ideally, the means for preventing slippage of the elastic seal is configurable to grip an object. The elastic seal may comprise at least one protrusion (or spline) that extends along the length of the inner tubular wall. For example, in some arrangements, the at least one protrusion may be arranged to extend from a first end of the concave bent portion to a second end of the concave bent portion. The first end of the concave bent portion may be located adjacent to the bridging portion. The second end of the concave bent portion may be located adjacent to the padding means. In other words, the concave bent portion may comprise the at least one protrusion. Ideally, the elastic seal may comprise a padding means. The padding means may be locatable on the first tubular member. The padding means may be locatable on the second tubular surface of the first tubular member. The padding means may be formable from and / or as part of the first tubular member. The padding means may be formable from and / or as part of the second tubular surface of the first tubular member. The padding means may extend along at least part of the length of the first tubular member. The padding means may comprise a padding section that is functionable as a reinforcement padding section for reinforcing the first tubular member. The at least one padding section may therefore be referred to as the reinforcement padding section. The reinforcement padding section may be configured to stabilise the first tubular member in the donning configuration. The reinforcement padding section may be configured to prevent the retraction of the elastic seal on the face of a wearer of the face mask assembly. The reinforcement padding section may be configured to prevent the pressing down of the elastic seal on the face of a wearer of the face mask assembly. The reinforcement padding section may be arranged to distribute the compressive stress associated with the first tubular member being prefabricated in the donning configuration. The reinforcement padding section may extend from the skirting portion of the first tubular member to the concave bent portion of the first tubular member. The reinforcement padding section may be substantially located on the outer surface of the first tubular member when the first tubular member. The reinforcement padding section may have an undulated profile. The reinforcement padding section may span at least part of or substantially the entirety of the circumference of the first tubular member. The reinforcement padding section may be homogenously formed as part of the first tubular member. The reinforcement padding section may comprise one or more pairs of reinforcement pads. Each pad of the one or more pairs of reinforcement pads may have substantially equal maximal thickness. Each pad of the one or more pairs of reinforcement pads may have a wave-like profile. Each pad of the one or more pairs of reinforcement pads has a variable thickness. The one or more pairs of reinforcement pads may comprise a first pair of reinforcement pads. The reinforcement padding section may comprise a second pair of reinforcement pads. The reinforcement padding section may comprise a third pair of reinforcement pads. Each pad of the one or more pairs of reinforcement pads may have substantially equal maximal thickness. In use, this equivalence in maximal thickness assists in distributing the compressive stress arising from the prefabrication of the first tubular member in the donning configuration. In arrangements where the one or more reinforcement pads comprises two or more pairs of reinforcement pads, each pair of reinforcement pads may be equispaced angularly about the circumference of the first tubular member. In use, this assists in evenly distributing the compressive stress arising from the deployment of the first tubular member in the donning configuration. This further assists in preventing the retraction of and pressing down of the elastic seal on the face of a wearer of the face mask assembly and further assists in stabilising the elastic seal in the donning configuration. The one or more pairs of reinforcement pads may be located on the outer surface of the first tubular member. In an advantageous arrangement, the padding means may comprise a nose pad. The nose pad may be homogenously formed as part of the elastic seal, and more particularly, the first tubular member. The nose pad may be configured to have a preformed shape. The nose pad may be located on the inner surface of the first tubular member. The nose pad may comprise a first nose pad portion and a second nose pad portion. The nose pad may be dimensioned such that an arch-shaped recess is defined by at least part of the first nose pad portion and at least part of the second nose pad portion. The first nose pad portion may be configured, in use, to plug a respective first concavity located on a first side of the nose bridge. The second nose pad portion may be configured, in use, to plug a respective second concavity located on a second side of the nose bridge. The nose pad may be configured, in use, to plug the concavities formed between the convexities on either side of the nose bridge. The nose pad may be adapted to seal around the nose bridge of the wearer of the face mask assembly. The nose pad may be configured, in use, to seal around the nose bridge of wearer of the face mask assembly such that curvature over the nose bridge is reduced. The nose pad may be operable to modify the contour of the nose bridge from a mixed convex-concave contour into a substantially convex contour. In other words, the nose pad may be operable to modify the contour of the sealing perimeter formed around the nose and mouth of a wearer from one with a mixed convex-concave contour to one with a substantially convex contour. In this way, the pressure exerted on the nose bridge is reduced. Advantageously, the nose pad may be configured to reduce and redirect the normal pressure for a given tangential tension around the facial contour being sealed around. The nose pad may be configured, in use, to extend along at least part of the nose bridge to distribute the normal force exerted on the nose and cheek of a user of the face mask assembly. Advantageously, this distribution of normal force reduces the pressure exerted on the user of a face mask assembly, thereby improving the comfort for the user. The nose pad may be configured, in use, to rest on the alae of the nose of a user of the face mask assembly. The first nose pad portion and the second nose pad portion may each comprise a resting portion that is arrangeable, in use, to rest on a respective ala of the nose of a wearer of the face mask assembly. Beneficially, the resting of the nose pad on the alae aids in stabilising the position of the face mask assembly on the face of a wearer of said assembly. Ideally, the mask frame may comprise at least one ring-shaped portion. The at least one ring-shaped portion may comprise a single ring-shaped portion or a plurality of ring-shaped portions. At least one, or each, ring-shaped portion may be circular or non-circular (e.g. polygonal, oval) in shape. At least one, or each, ring-shaped portion may define a respective mask frame aperture therein. The at least one ring-shaped portion may include a ring-shaped portion that is arranged, in use, to support the securement of a connecting means (e.g. a vent ring) for connecting the face mask assembly to a CPAP machine In embodiments where the mask frame comprises a single ring-shaped portion, said mask frame portion may define the mask frame aperture arranged, in use, to support the securement, within the mask base aperture, of a connecting means, (e.g. a vent ring) for connecting the face mask assembly to a CPAP machine. In preferred embodiments, the at least one ring-shaped portion, and more particularly, the plurality of ring-shaped portions may comprise a first ring-shaped portion and a second ring portion bridged to the first ring-shaped portion via one or more bridging members. The first ring- shaped portion may therefore define a first mask frame aperture. The second-ring shaped portion second may define a second mask frame aperture. The first ring-shaped portion and the second ring-shaped portion are concentrically arranged with respect to each other. In these arrangements where the first ring-shaped portion is, preferably, an innermost ring-shaped portion and the second ring-shaped portion may be an outermost ring-shaped portion. Alternatively, the second ring-shaped portion can be an outer ring- shaped portion, such as, for example, an intermediate ring portion disposed between the innermost ring-shaped portion and one or more ring-shaped portions. The innermost ring portion is, preferably, the ring-shaped portion that is arranged in use to support the securement, within the mask base aperture, of a connecting means (e.g. a vent ring) for connecting the face mask assembly to a CPAP machine. Beneficially, the inclusion of a first ring-shaped portion and a second ring-shaped portion bridged to the first-ring shaped portion improves structural strength and prevents blow-out of the mask base during usage of the face mask assembly when air pressure is high, such as when the face mask assembly is used during CPAP therapy. In embodiments where the mask frame comprises an innermost ring-shaped portion and an outermost ring-shaped portion, the one or more attachment means may extend from the outermost ring-shaped portion. Ideally, the elastic seal, when donned on the face of a user of the face mask assembly via the first tubular member, is collapsible in height under compression. It will be understood here that height here refers to the distance between the opening defined between the first end of the elastic seal comprising the sealing perimeter and the second end of the elastic seal comprising the mask base. For example, in embodiments where a harness is used to secure, and more particularly, compressively secure the elastic seal to the face of a wearer of the face mask assembly, the elastic seal may be collapsible from a rest state to a compressed state. Accordingly, the elastic seal, when donned on the face of a user of the face mask assembly via the first tubular member, is collapsible to a compressed state, and in particular, is collapsible to the compressed state via usage of a harness. In the compressed state, the first tubular member may be configured to be packed within, or at least partially encapsulated by the second tubular member under compression, such as when a harness is used to secure the elastic seal to the face of a wearer in a face mask assembly (e.g. in a compressive securement arrangement). In other words, the first tubular member of the elastic seal may be packable within or at least partially encapsulatable by the second tubular member under compression, such as when a harness is used to secure the elastic seal to the face of a wearer of the face mask assembly (e.g. in a compressive securement arrangement). In this way, the second tubular member may be configured to function as buttress for the first tubular member in the collapsed state. Advantageously, the first tubular member being packed within or at least partially encapsulated by the second tubular member mitigates expansion of the first tubular member resulting from application of the elastic seal on the face of a user of the face mask assembly, and more preferably resulting from application of the elastic seal on the face of a user of the face mask assembly, said face mask assembly being used as a CPAP face mask assembly during CPAP therapy. The second tubular member may be configured to seal around the first tubular member under a compressive force. In particular, the elastic seal, when donned on the face of a user via the first tubular member, is preferably compressible such that the second tubular member is configured to seal around the first tubular member. In this way, the second tubular member being configured to seal around the first tubular member thereby enables formation of a further (or second) seal around the seal formed between the first tubular member and the object to which the elastic seal is being applied (e.g. the face of the wearer of a face mask assembly comprising the elastic seal). This further seal may also be referred to as the external seal, and the seal formed between the first tubular member and the object to which the elastic seal is being applied may be referred to as the internal (or first) seal. Advantageously, the implementation of this external seal helps to buffer against the compressive force exerted on the face of a user of the face mask assembly via application of the harness (e.g. when the harness is in a compressive securement arrangement). It will therefore be understood that the elastic seal may comprise a buffering region to buffer against the compressive force exerted on the face of a user of the face mask assembly via application of the harness to secure, and preferably, compressively secure the elastic seal to the face of the wearer of the face mask assembly. In some arrangements, the second tubular member may be arranged to seal around the first tubular member under compression by splaying outwards as a result of said compression and, preferably, to accommodate the packing or partial encapsulation of the first tubular member therein. The second tubular member may be arranged to splay outwards when the elastic seal is under compression, and, preferably, may be configured to accommodate the packing or partially encapsulation of the first tubular member in the splayed configuration. In this way, additional elastic seal material is packed more tightly in the space between the first tubular member and the second tubular member in order to buffer against the compressive force exerted on the face of a user of the face mask assembly through the harness. In other arrangements, the second tubular member may be configured to seal around the first tubular member under compression by partially collapsing under compression to create folds in an inward facing surface of the second tubular member. In other words, the first tubular member may be configured to be packed within, or at least partially encapsulated by the folds formed in an inward facing surface of the second tubular member that has partially collapsed to form the external seal around the first tubular member. In this way, additional elastic seal material is packed around the first tubular member in order to buffer against the compressive force exerted on the face of a user of the face mask assembly through the harness. In each of the abovementioned arrangements, the elastic seal comprises a buffering region for absorbing at least part of the compression force exerted on the face of a wearer of the face mask assembly via application of the harness. In this way, the face of a user of the face mask assembly may experience less pressure during usage of the face mask assembly because of the absorption of some of the compressive force exerted by the harness on the elastic seal, thereby improving the comfort for a user of such a face mask assembly. In some arrangements, the buffering region may comprise the bridging portion and / or at least part of the first tubular member of the elastic seal. The at least part of the first tubular member may comprise the bent portion. In some arrangements, the buffering region may comprise the folds formed in an inward facing surface of the second tubular member that has partially collapsed to form the external seal around the first tubular member. Ideally, the elastic seal, when donned on the face of a user of the face mask assembly via the first tubular member, is compressible such that the bent portion of the first tubular member is packed within and / or at least partially encapsulated by the second tubular member. In use, this packing of additional seal material between the first tubular member and second tubular member assists in buffering against the compressive force exerted on the face of a wearer of the face mask assembly. Ideally, the face mask assembly may further comprise a harness arranged to support the elastic seal on the object. Preferably, the harness may be coupled to the elastic seal. The harness may be coupled directly and / or indirectly to the elastic seal. Preferably, the harness may be coupled to the mask body. Preferably, the harness may be coupled directly and / or indirectly to the mask body. Preferably, the harness may be coupled directly and / or indirectly to a mask body that is integrated into the elastic seal to support the elastic seal on the object. Ideally, the harness may comprise one or more straps. In some embodiments, the, or each, strap may be a single-layered strap. In some embodiments, the, or each, strap may comprise a plurality of strap layers. Ideally, the one or more straps may comprise a first strap and a second strap. Optionally, the first strap may be interconnected to the second strap by an interconnecting strap. Each strap is securable directly and / or indirectly to the elastic seal and / or mask body via one or more attachment means. In some arrangements, the one or more attachment means may form part of the mask body integrated into the elastic seal. That is, the mask body may comprise one or more attachment means arranged for the securement of one or more straps of a harness thereto. Each strap is securable directly and / or indirectly to one or more attachment means forming part of the mask body integrated into the elastic seal. In other arrangements, the attachment means need not form part of the mask body and may instead be separate to the mask body. In these arrangements, the one or more attachment means may be integrated into the elastic seal (e.g. through overmoulding for example). The one or more attachment means may be located within and / or on a surface of the second tubular member and / or the mask base. The harness may be securable directly and / or indirectly to the one or more attachment means to compressively secure the elastic seal to the face of the wearer of the face mask assembly. Each strap may be securable indirectly to one or more attachment means via an intermediary coupling member, said strap being securable directly to the intermediary coupling member. Each strap may be securable directly and / or indirectly to the elastic seal and / or one or more attachment means via at least one securing means for securing the harness to the elastic seal and / or mask body. Ideally, each strap is adjustable so as to control the force with which the elastic seal is pulled onto the face of a user of the face mask assembly. Each strap may be adjustable so as to control the force with which the elastic seal is pulled onto the face of a user via adjustment of the at least one securing means. Accordingly, the, or each, securing means is operable to adjust the force with which the elastic seal is pulled onto the face of a user of the face mask assembly. The, or each, securing means may comprise a securing loop formable from use of at least one fastener. The fastener may comprise a hook-and-loop fastener. The hook-and-loop fastener may comprise a hook-and-loop fastening layer. The hook-and-loop fastening layer may form at least one layer of the plurality of strap layers and accordingly, this layer may also be referred to as the securing layer. Alternatively, in embodiments where each strap is a single-layered strap, the single-layered strap may be the securing layer. In more detail, the securing layer comprises a first securing layer surface, one or more hooking means and a second securing layer surface. The first securing layer surface comprises a loop portion located on at least part of, or all of, the first securing layer surface. The second securing layer surface may be a non-loop layer surface. By non-loop layer surface, it will be understood that this surface does not comprise loops for engaging with the hooking means. Each strap may comprise a first hooking means located at a first end of the strap, and a second hooking means located at a second end of the strap, said second end being distal to the first end of the strap. The, or each, hooking means may comprise a hooking patch for fastening to the loop portion of the first securing layer surface. The hooking patch may comprise a first hooking surface for fastening to the loop portion, and a second hooking surface for fastening to the loop portion. The hooking patch is fastenable, and more preferably, detachably fastenable to a first part of the loop portion via the first hooking surface. The fastened hooking patch that is fastened on the first part of the loop portion is fastenable, and more preferably, detachably fastenable to a second part of the loop portion, via the second hooking surface so as to form the securing loop. Beneficially, the ability to detachably fasten the hooking patch enables a user of the face mask assembly to control the force with which the elastic seal is pulled onto an object, such as the face of a wearer of the face mask assembly. In embodiments where the strap comprises a plurality of layers, the strap may comprise a backing layer. The backing layer may comprise a first backing layer surface and a second backing layer surface. The backing layer may be an inelastic layer. The backing layer may be a flexible layer. The backing layer, and in particular, the first backing layer surface is configured to engage with the second layer of the securing layer. Beneficially, where the backing layer is inelastic and flexible, the backing layer is configured to prevent narrowing and twisting of the strap so as to prevent a twisted strap abrasively rubbing against the face of a user of the face mask assembly. In embodiments where the strap comprises a plurality of strap layers, the strap may comprise an elastic strap layer. The elastic strap layer may be formed from silicone and may be referred to as a silicone strap layer. The silicone strap layer is functionable as a non-slip strap layer. Beneficially, the usage of a silicone, when in contact with skin, results in a high coefficient of friction, thereby enabling the silicone strap layer to function as a non-slip layer in use. The elastic strap layer is configured to, in use, to stretch in a transverse and longitudinal direction. The elastic strap layer is an auxetic strap layer and / or is demonstrates quasi-auxetic behaviour. Beneficially, the elastic strap layer is arranged to spread the normal force that is generated in response to tension generated in the strap so as to increase the area of contact with the skin of the user of the face mask assembly, thereby reducing the pressure exerted which mitigates any risk of discomfort and skin damage during usage of the face mask assembly. In an embodiment, the elastic seal may comprise at least one recess sized to accommodate part of the mask body. In an embodiment, the mask frame comprises a three-dimensional shell comprising a top panel, and a plurality of side panels extending from the top panel. In another embodiment, the mask frame comprises a pleated frame. Preferably, the pleated frame is a fully pleated frame. Preferably, the mask frame is configurable to provide structural support and flexibility to the mask body. Ideally, the mask frame is formable from a material configured to provide structural support and flexibility. The material configured to provide structural support and flexibility may also be known as a semi-rigid material. Advantageously, the use of a material configured to provide structural support and flexibility enables the mask frame to retain the shape of the three-dimensional shell or pleated frame whilst also enabling the frame to adapt to shape changes in the user’s face during usage of the face mask assembly. Ideally, the mask frame may be formed from material configured to provide structural support and flexibility such as mylar. Ideally, the face mask assembly is functionable as a CPAP face mask assembly. The face mask assembly may be useable for non-invasive and minimally invasive ventilation applications. The face mask assembly may be connectible to a CPAP machine. The elastic seal, and in particular the mask base of the elastic seal and / or the mask body may be connectible to a CPAP machine. The face mask assembly may also be connectible to a mechanical ventilation system for mechanical ventilation of the lungs. The mask body may comprise a mask frame that is integrally formed with the elastic seal, and more preferably integrally formed with the mask base of the elastic seal. The mask body may be integrated into the mask base of the elastic seal. The mask frame of the mask body may be integrated into the elastic seal. Ideally, the face mask assembly may be configured to maintain an airtight seal around the nose and mouth of the wearer at a positive pressure of at least 5 cmH2O. The face mask assembly may be configured to maintain an airtight seal around the nose and mouth of the wearer at a positive pressure of at least 10 cm H2O.The face mask assembly may be configured to maintain an airtight seal around the nose and mouth of the wearer at a positive pressure of at least 15 cmH2O. The face mask assembly may be configured to maintain an airtight seal around the nose and mouth of the wearer at a positive pressure of at least 20 cmH2O. The face mask assembly may be connectible to a CPAP machine. The mask base may comprise a mask base aperture for securing objects therein and / or thereto. In embodiments where the face mask assembly is used as a face CPAP face mask assembly, the mask base aperture may be arranged to secure a connecting means, such as a vent ring, for connecting a CPAP machine to the face mask assembly. The vent ring may comprise tubing attached to the vent ring. The mask body, and particularly the mask frame, comprises a mask frame aperture. The mask frame aperture may have a diameter greater than the diameter of the mask base aperture. The mask body, and more preferably, the mask frame may be arranged to support the securement of the connecting means for connecting the face mask assembly to a CPAP machine within the mask base aperture. The mask body may comprise one or more attachment means extending from the mask frame. In some embodiments, where the mask body comprises a mask frame that is integrated into the mask base of the elastic seal, the, or each, attachment means may extend through the elastic seal. In these embodiments, the, or each, attachment means may extend through a corresponding slit formed within the mask base for protrusion of the attachment means therethrough. In other embodiments, the mask body may be separate from and securable within and / or to the elastic seal. In these embodiments, the mask body may be arranged to directly secure the connecting means for connecting a CPAP machine to the face mask assembly. The, or each, attachment means is configured for a harness to be coupled directly and / or indirectly thereto. The, or each, attachment means may comprise one or more attachment loops. Beneficially, in embodiments wherein the, or each, each strap of the harness is coupled directly and / or indirectly to one or more attachment loops, each loop is rotatable, in use, about a first orthogonal axis, said first orthogonal axis being the longitudinal axis of the attachment loop, a second orthogonal axis and a third orthogonal axis, wherein rotation about the first orthogonal axis provides each strap directly and / or indirectly coupled to a respective attachment loop with an additional torsional component to the tangential pull exerted by the, or each, strap. This enables the face mask assembly to accommodate different head pull directions associated with user’s having different head shapes and sizes. The face mask assembly may comprise one or more intermediary coupling members for indirectly coupling the harness to the elastic seal and / or mask body. The harness may be indirectly coupled to one or more attachment means of the mask body via the one or more intermediary coupling members. The one or more intermediary coupling members may comprise one or more coupling loops, such as circular loops. The one or more intermediary coupling members are configured to enable angular adjustment of the harness in use. In particular, in embodiments wherein each strap comprises a securing means that is operable, in use, to form a securing loop, the securing loop may be securable to a respective coupling loop and is slidable about the respective loop. Beneficially, this provides the face mask assembly with the ability to accommodate different three-dimensional shapes associated with users of the face mask assembly. According to an eleventh aspect of the present disclosure, there is provided an elastic seal for a face mask assembly, wherein the elastic seal comprises: a first tubular member that is arranged for forming a sealing perimeter around the face of a wearer, a second tubular member, and a bridging portion; wherein the elastic seal is prefabricated such that it has a single stable state configuration, wherein the single stable state configuration is a donning configuration. The elastic seal may comprise any of the features as described for the elastic seal in the tenth aspect of the disclosure. According to a twelfth aspect of the present disclosure there is provided a continuous positive airway pressure (CPAP) system, the CPAP system comprising: a CPAP machine; and a face mask assembly comprising an elastic seal, wherein the elastic seal comprises: a first tubular member that is arranged for forming a sealing perimeter around the face of a wearer, a second tubular member, and a bridging portion; wherein the elastic seal is prefabricated such that it has a single stable state configuration, wherein the single stable state configuration is a donning configuration. The face mask assembly may comprise any of the features of the face mask assembly described above in relation to the tenth aspect of the disclosure. The face mask assembly is connectable to the CPAP machine. The elastic seal may comprise a mask base. The face mask assembly may comprise a connecting means for connecting a CPAP machine to the face mask assembly. The connecting means may comprise a vent ring. The CPAP system may further comprise tubing for coupling the connecting means to the CPAP machine. The connecting means, and in particular, the vent ring may be arranged to be secured within a mask base aperture of the mask base of the elastic seal. BRIEF DESCRIPTION OF THE DRAWINGS Examples of the present disclosure will now be described with reference to the accompanying drawings, in which: Figure 1 shows an example elastic seal applied around an object; Figures 2A to 2D show a variety of facial structures accommodating an example elastic seal; Figure 3A shows an example elastic seal applied around an object with a convex cross- section; Figure 3B shows an example elastic seal applied around an object with a non-convex cross-section; Figure 4 shows the slanted coronal sections of the human head around the nose and the mouth; Figures 5 to 6 are perspective views of the elastic seal according to aspects of the present disclosure; Figure 7 is a cross-sectional view of the elastic seal according to aspects of the present disclosure; Figure 8 is a perspective view of the elastic seal according to aspects of the present disclosure; Figure 9 is cross-sectional view of the elastic seal shown in Figure 8; Figure 10 is an illustration of the employment of the elastic seal on a human face. Figure 11 is a perspective view of a partially assembled face mask assembly according to aspects of the present disclosure without the filter means; Figure 12 is a bottom view of the partially assembled face mask assembly as shown in Figure 11; Figures 13 and 14 show cross-sectional views of the partially assembled face mask assembly as shown in Figure 11; Figure 15 shows a perspective view of the filter means according to aspects of the present invention; Figure 16 shows a top-down view of the filter means as shown in Figure 15. Figures 17 and 18 are perspective views of an embodiment of the elastic seal according to aspects of the present disclosure; Figure 19 is a perspective view of the means for filtering inhaled and / or exhaled air by electrostatic attraction; Figure 20 is a cross-sectional perspective view of the means for filtering inhaled and / or exhaled air by electrostatic attraction as illustrated in Figure 18; Figure 21 is a cross-sectional view of the embodiment of the elastic seal as shown in Figures 17 and 18; Figure 22 is a cross-sectional perspective view of the embodiment of the elastic seal as shown in Figures 17,18 and 21. Figure 23 is a cross-sectional view of an embodiment of the face mask assembly according to aspects of the present disclosure; Figure 24 is a perspective cross-sectional view of the embodiment of the face mask assembly shown in Figure 23; Figure 25 is a perspective view of an embodiment of the mask frame and fixing means according to aspects of the present disclosure; Figure 26 is a side-view of the embodiment of the mask frame as shown in Figure 25; Figure 27 is a front-view of the embodiment of the mask frame as shown in Figure 25; Figure 28 is a perspective view of an embodiment of the filter means according to aspects of the present disclosure; Figure 29 is a side-view of the embodiment of the filter means as shown in Figure 28; Figure 30 is a front-view of the embodiment of the filter means as shown in Figure 28; Figure 31 is a perspective view of an embodiment of the mask body according to aspects of the present disclosure; Figure 32 is a side-view of the embodiment of the mask body as shown in Figure 31; Figure 33 is a front-view of the embodiment of the mask body as shown in Figure 31; Figures 34A to D show an example of how airflow interacts with the pleats of the filter means according to the present disclosure; Figures 35A to C show an example of how a means for absorbing fluids may be cut and rolled into a truncated cone configuration for application on the face of a user of a face mask assembly; Figures 36 and 37 are perspective views of an embodiment of the face mask assembly according to aspects of the present disclosure; Figure 38 shows a perspective view of the straps of the harness of the face mask assembly shown in Figures 36 and 37, with the straps being interconnected with an optional interconnecting strap. Figure 39 shows a partial cross-sectional view of a strap forming part of the harness for the face mask assembly as shown in Figures 36 and 37. Figure 40 shows a partial perspective view of the strap shown in Figure 39. Figure 41 shows a partial cross-sectional view of a strap forming part of the harness of the face mask assembly in Figures 36 and 37, with the strap having a securing loop. Figure 42 shows a partial perspective view of the strap as shown in Figure 41. Figure 43 shows a partial perspective view of the strap as shown in Figure 41 when it is being stretched. Figure 44 illustrates the quasi-auxetic behaviour of the elastic layer of the strap as shown in Figure 41. Figures 45 and 46 are perspective views of the elastic seal having an integrated mask body which forms part of the face mask assembly as shown in Figures 36 and 37. Figure 47 is a cross-sectional perspective view of the elastic seal having an integrated mask body as shown in Figures 45 and 46, with the elastic seal being in the rest configuration. Figure 48 is a cross-sectional perspective view of the elastic seal having an integrated mask body as shown in Figures 45 and 46, with the elastic seal being in the inverted configuration. Figures 49 and 50 are a first plan view and a second plan view of the elastic seal having an integrated mask body as shown in Figures 45 and 46. Figures 51 is a perspective view of a further embodiment of the face mask assembly according to aspects of the present disclosure. Figure 52 is a perspective cross-sectional view of the face mask assembly shown in Figure 51. Figure 53 is a perspective view of the face mask assembly shown in Figure 51 in the compressed state. Figure 54 is a perspective cross-sectional view of the face mask assembly shown in Figure 53. Figure 55 is a bottom view of the face mask assembly as shown in Figure 51, wherein the mask body integrated into the mask base of the elastic seal is illustrated. Figure 56 is a side view of the face mask assembly as shown in Figure 51, wherein sections of the inner tubular member are shown to illustrate the padding means and skirting portion of the face mask assembly shown in Figure 51. Figure 57 is an exploded cross-sectional view of a nose pad forming part of the elastic seal of the face mask assembly shown in Figure 51 and the slanted coronal cross-section of the nose-mouth contour near the nose bridge, as shown in Figure 4. Figure 58 is a cross-sectional view of the sealed arrangement formed by the sealing of the nose pad around the nose-mouth contour shown in Figure 57. Figure 59 is a perspective view of the nose pad shown in Figures 57 and 58. Figure 60 shows a three-dimensional perspective view of an example nose-mouth contour of a wearer of the face mask assembly. Figure 61 shows the face mask assembly as shown in Figure 51 sealing around the nose- mouth contour of the wearer of the face mask assembly. Figure 62 is a perspective cross-sectional view of the face mask assembly as shown in Figure 61. DETAILED DESCRIPTION The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of various embodiments of the disclosure as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the various embodiments described herein can be made without departing from the scope and spirit of the disclosure. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness. The terms and words used in the following description are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the disclosure. Accordingly, it should be apparent to those skilled in the art that the following description of various embodiments of the disclosure is provided for illustration purpose only and not for the purpose of limiting the disclosure as defined by the appended claims and their equivalents. It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. The present disclosure relates to a face mask, elastic seal and mask body. The elastic seal can be included as part of the face mask but this is not required in all examples. The elastic seal may be provided in isolation and may be used for forming seals around other objects. The elastic seal is not limited to use as a face mask seal for forming a sealing perimeter around the nose and mouth of the wearer although this is an advantageous implementation. The mask body may be provided in isolation. The mask body may be used with the elastic seal to form the face mask but this is not required in all examples. The mask body may be used with other forms of face mask seals. To aid in the understanding of elastic seals, an explanation of the forces applied when an elastic seal is applied around different shapes is provided. When an elastic seal is applied around a tubular object it forms a parallel seal due to the overlap in area between the elastic seal and the object as well as a perpendicular seal. The perpendicular seal is caused due to the normal force pressing the elastic seal against the sealed object generated by the tangential tension within the elastic seal. An elastic seal is inherently capable of changing its dimensions. An elastic seal forms a tight seal around a tubular object such as a cylinder. It will be appreciated that, the more the elastic seal is stretched around a tubular object, the tighter the resultant seal. When an elastic seal is applied around a cylinder, for a tangential tension T , the normalforce N exerted on a short circular arc of radius of curvature ^ and length ^ s is given by:^ 2T NˆT(1) wheren̂^ N ^ sis the normal force per unit length of the arc. An example elastic seal may have a length of 2^ R in its neutral relaxed (unstretched)state and an elasticity constant k , ^ ^ R ^ ^ R , then:T ^ k ^2^ ^ ^ R ^ ^ 2 ^ k ^ ^ RSubstituting equation (2) into equation (3): nˆ ^ T^ k2^^^ R^ 2 ^ R^ R^k R^ R ^1^ ^ R RThe larger the strain ^ R R on the elastic seal (i.e. the more is stretched or thelarger the radius of curvature the object it is put around), the higher the normal force per unitlength n̂ pressing the elastic seal against the object. Therefore, the more an elastic seal isstretched around a tubular object, the tighter the seal between the two. Figure 1 shows an example elastic seal 100 applied around an object with a sloped surface. The object is a circular cone. The elastic seal 100 comprises a first end 104 defining a first opening (not shown) and a second end 108 defining a second opening (not shown) in communication with the first opening. A sidewall 112 extends between the first end 104 and the second end 108. In this example, the first and second openings are circular when the elastic seal is unstretched and have the same diameter. The elastic seal 100 has been stretched to accommodate the object. The elastic seal 100 is therefore under tension, and exerts a centripetal (i.e. directed towards and perpendicular to thelongitudinal axis of a cone) force n̂ per unit length on the sloped surface as indicated by thearrows 8 pointing towards the centre of the cone. Ashort arc of the elastic seal 100 can be considered as generating a normal force of Non the cone in the direction of the arrows 8. The tangential force F^ sliding the elastic seal 100 up the sloped surface (as indicated by the arrows 9) and thus away from the object is given by: F^^ N sin ^(4)Where ^ is the slant angle of the object.The normal force pressing the elastic seal 100 against the sloped surface F^(as indicated by the arrows 10) is given by: F^ ^ N cos ^ (5)The normal force F^ generates a frictional force F f that acts against other tangentialforces to prevent relative movement between the elastic seal 100 and the surface up to a maximum value (the traction): F f^^ F^^ ^ Ncos^(6)where ^ is the coefficient of friction between the elastic seal 100 and the sloped surface.In order for the elastic seal 100 not to slip on the sloped surface: ^^ N sin^ ^ ^ N cos ^ ^ tan^ ^ ^ Whether the a circular conetowards the apex depends only on the slant angle ^ and the friction of coefficient ^ . Slipping isprevented by reducing the slant angle ^ or increasing the friction of coefficient ^ . An elastic sealmay stay stably on the sloped surface of a pointed cone (small slant angle ^ ) but will tend to rolloff the sloped surface of a squat cone (large slant angle ^ ).An elastic seal, in isolation, can form an effective seal around objects such as cylindrical or conical objects. However, it can be more challenging to form a seal around a dome-shaped object. Increasing the tension T in the elastic seal increases the normal force N pressing theelastic seal against the sloped surface and improves the tightness of the seal but may not prevent slippage of the elastic seal. This means that an elastic seal, in isolation, may form an effective seal enclosing the nose and mouth for the wearer for animals with more conical rather than dome- shaped facial profiles. For example, an effective seal can be formed for animals with a long snout (Figure 2A), but not necessarily for animals with a short snout (Figure 2B). For humans, the human nose points predominantly downwards and only slightly forwards, resulting in a relatively flat face and not a very favourable geometry for an elastic seal (Figure 2C), especially in the presence of a heavy jowl (Figure 2D). Forming a seal can also be challenging due to the Poisson effect. The Poisson effect refers to how materials deform oppositely in directions perpendicular to that of the primary loading. When an elastic seal is stretched (positive strain in length), it becomes narrower (negative strain in width), and vice versa. As an elastic seal stretches around the sealed object and lengthens, it becomes narrower in its width, resulting in a smaller area of overlap with the sealed object’s surface. The reduction in overlap area may undermine the tightness of the seal. Elastic seals will form an effective seal around objects with convex cross-sections. Here, a convex cross-section will be understood to refer to all of the interior angles being approximately less than 180 degrees. An example elastic seal 100 forming a seal around an object with a convex cross-section is shown in Figure 3A. However, an elastic seal 100 may not completely seal around an object if its cross-section is non-convex and contains concavities (roughly, some interior angles are > 180^), as the elastic seal 100 will tend to be strung taut across the concavities by the adjacent convexities (Figure 3B). The nose-cheek triangles of the human skull are two such concavities that may prevent an elastic seal from forming an effective seal around the nose and the mouth of a human wearer. Therefore, while elastic seals 100 can form an effective seal against some objects such as some forms of facial shapes, an elastic seal 100 can struggle to form an effective seal around all objects and in particular around human faces which tend to form an approximate dome shape with a non-convex cross-section. Figure 4 better exemplifies why this is problematic for humans, wherein the slanted coronal section of the human head around the nose and the mouth is shown as being convex-concave near the tip of the nose, largely convex over the middle part of the nose, and convex-concave near the nose bridge. Aspects of the present disclosure are directed towards improved elastic seal constructions to overcome these problems. In Figures 5-7, there is provided an elastic seal 200 according to the present invention having an inner tubular member 201, a bridging portion 202 and an outer tubular member 203. The outer tubular member is optional when deployed within a face mask assembly 300. In this non-limiting example, the bridging portion 202 bridges between the inner tubular member 201 and the outer tubular member 203. At least part of the seal 201 is invertible to form a sealing perimeter around the nose and mouth of a wearer. Additionally, at least part of the elastic seal 201 is invertible to form a sealing perimeter around the mouth and nose and / or eyes of a wearer. The at least part of the elastic seal 201 that is invertible to form a sealing perimeter is the inner tubular member 201. The inner tubular member 201 is configured to form a sealing perimeter around the nose and mouth of a wearer. Additionally, the inner tubular member 201 is configured to form a sealing perimeter around the mouth and nose and / or eyes of a wearer. The inner tubular member 201 is invertible. The inner tubular member 201 is invertible to form a sealing perimeter around the nose and mouth of the wearer. The inner tubular member 201 is invertible to form a sealing perimeter around the nose and mouth and / or eyes of the wearer. In this example, the inner tubular member 201 has a circular cross-section, albeit other types of cross-sections are within the scope of the patent specification. The inner tubular member 201 has a first inner tubular member surface 204a and a second inner tubular member surface 204b. The elastic seal 200 is invertible from a rest configuration to a deployed configuration, as best exemplified by Figures 5 to 9. It will be understood here that, as shown, the deployed configuration may also be referred to as the inverted configuration. More specifically, the inner tubular member 201 is invertible from a rest configuration to a deployed configuration. In the rest configuration, as best shown in Figure 7, the first tubular surface 204a is an inner tubular surface, and the second tubular surface is an outer tubular surface 204b. In use, the inner tubular member 201 is invertible from the rest configuration to the deployed configuration such that the second tubular surface 204b is inverted from being an outer tubular surface 204b to an inner tubular surface 204b adapted for forming a sealing perimeter around the nose and mouth of a wearer. Additionally, in use, the inner tubular member 201 is invertible from the rest configuration to the deployed configuration such that the second tubular surface 204b is inverted from being an outer tubular surface 204b to an inner tubular surface 204b adapted for forming a sealing perimeter around the nose and mouth of a wearer and / or eyes of a wearer. Figures 8 and 9 show the elastic seal 200 of the present invention in the inverted configuration. In the inverted configuration a shape-receiving opening 205 is located at an end of the inner tubular member. The shape-receiving opening 205 is configured to receive the face of the wearer of the mask. The shape-receiving opening 205 is configured to be flexible and adaptable to the shape being received. Figure 10 shows the elastic seal 200 in the deployed configuration on the face of a wearer. The elastic seal 200, and more specifically, the inner tubular member 201, is configured to form an effective sealing perimeter for a variety of facial shapes and is able to maintain the sealing perimeter as the wearer opens their mouth. In a non-limiting example as best shown in Figure 10, in the deployed configuration, the elastic seal 200 is configured to seal around a shape having a first contour having a convex curvature and a second contour having a convex and concave curvature. More specifically, the bridging portion 202 is configured to form a seal around the first contour having a convex curvature and the inner tubular member 201 is configured to form a seal around the second contour having convex and concave curvature. The inner tubular member 201 is adapted for forming an effective seal around a shape having a convex and concave curvature. In the rest configuration, the first tubular surface 204a has a smaller surface area than the second tubular surface 204b, as best shown in Figure 5. In use, the inner tubular member 201 is invertible from the rest configuration to the deployed configuration, wherein the inner tubular member 201 is configured to form a bend 206 to minimise the potential energy stored in the elasticity of the seal in the deployed configuration, as best shown in Figure 9. More specifically, in the deployed configuration, the bend 206 has a concave curvature. In the deployed configuration, the recoil of the bend 206 exerts a force to urge the inner tubular member 201 to seal around the nose and mouth of the wearer. More specifically, in the deployed configuration, the recoil of the bend 206 exerts a force to urge the inner tubular member 201 to seal around a shape having convex and concave curvature such that the inner tubular member 201 thereby forms an effective sealing perimeter around the convex and concave curvature of the shape. In the deployed configuration, the elastic seal 200, and more specifically, the inner tubular member 201 is configured to provide concentric contraction around and centripetal radial compression across the inner tubular member 201 to increase the friction between the elastic seal 200 and face of the user and to prevent the elastic seal 200 from slipping off the face of the user. In preferred embodiments, the inner tubular member 201 has an inner tubular member length and the outer tubular member 203 has an outer tubular member length. The inner tubular member length may be the same as, or different to, the outer tubular member length. The inner tubular member 201 and the outer tubular member 203 are axially aligned and extend co-axially in the same direction. Further aspects of the present disclosure relate to a face mask assembly 300 that can be used with the elastic seals 200 described above. In Figures 11 to 16 there is shown the face mask assembly 300, generally denoted by the reference numeral 300, having an elastic seal 200 and a mask body 400, the elastic seal 200 having an inner tubular member 201, a bridging portion 202 an outer tubular member 203. The face mask assembly 300 has a mask base 207. In a non-limiting example of the embodiment shown, the bridging portion bridges between the inner tubular member 201 and the outer tubular member 203. The mask body 400 has a filter 500 and a mask frame 401. In one embodiment, the mask body 400 is detachably connected to the elastic seal 200. In preferred embodiments, the mask body 400, and more specifically, the mask frame 401 is secured to or within the elastic seal 200. More specifically, the mask frame 401 is secured to or within the elastic seal 200. The filter 500, as shown in non-limiting embodiments shown in Figure 15 and 16 may be detachably connected to the elastic seal 200 and / or mask frame 401 by use of a fixing arrangement. The fixing arrangement (not shown) may be any suitable arrangement to secure the filter 500 in use to the elastic seal 200 and / or mask frame 401. In one example, the filter 500 may be secured between the mask frame 401 and the elastic seal 200 using the fixing arrangement. The filter may be secured using the fixing arrangement via at least one aperture, and more specifically, a plurality of apertures 510 configured to receive the fixing arrangement. In one embodiment, when using the fixing arrangement, the filter may drape over the mask frame. In another embodiment, the filter may conform to the mask frame fixed using the fixing arrangement such that it conforms to the shape of the mask frame. The mask frame 401 is a three-dimensional shell 401 having a top panel 402, and a plurality of side panels 403 extending from the top panel 402. The side panels 403 extend vertically downwards from the top panel 402. The mask frame 401 is configured to provide structural support and flexibility to the mask body 400. The mask frame 401 is formed from a material configured to provide structural support and flexibility. The material configured to provide structural support and flexibility may also be known as a semi-rigid material. The use of a material configured to provide structural support and flexibility enables the mask frame 401 to retain the shape of the three-dimensional shell 401 whilst also enabling the frame 401 to adapt to shape changes in the user’s face during usage of the mask. In an advantageous embodiment, the material configured to provide structural support and flexibility is mylar. In a non-limiting example as best shown in Figure 11, the mask frame 401 is formed from a single folded sheet of material configured to provide structural support and flexibility without any joints formed by welding, sewing, adhesives, or other attachment methods. A single sheet of material is folded to form the mask frame. This simplifies the construction of the mask frame 401 as separate elements are not required to be attached together to form the mask frame 401. The absence of joints that require attachment reduces the risk of leakage and simplifies the manufacturing process. The top panel 402 has at least one pleat 404. The at least one pleat may be formed by folding the material of the mask frame 401. The at least one pleat increases the surface area of the mask frame 401 available for filtration without increasing the mask volume. This means that the mask frame 401 provides a lower airflow resistance. Breathing is easier for the wearer as there is lower airflow resistance and hence lower inspiratory pressure is required. Moreover, the breathing is more energy efficient as there is less dead space to ventilate for the wearer. Furthermore, the at least one pleat 404 provides additional rigidity to the mask frame which means that the mask frame is less likely to collapse and wrap around the wearer’s nose and mouth during inhalation. The at least one pleat 404 provides additional rigidity without increasing the bulk and weight of the mask frame 401. The at least one pleat 404 enables the mask frame 401 to increase in size when the wearer opens their mouth. The at least one pleat 404 can function as a bellow when actuated by the jaw muscles of the wearer to refresh the air in the mask, aid the wearer’s breathing, or force out water vapour that may otherwise condense into droplets within the mask. This bellow function can be intentionally activated by the wearer or may occur coincidentally such as when the wearer speaks. The at least one pleat 404 is a plurality of pleats 404. In a non-limiting example, each pleat of the plurality of pleats 404 is arranged parallel to one another along the top panel 402. The pleats 404 enable the mask frame 401 to increase its vertical dimension (direction perpendicular to the pleats) while maintaining its horizontal dimension (direction parallel to the pleats) when the wearer opens their mouth. The mask frame 401 has at least one aperture 405, in particular, a plurality of apertures 405. In a non-limiting example, the plurality of apertures 405 is located on the top panel 402 and the plurality of side panels 403. The at least one aperture 405 is configured to enable the user to breathe easier by lowering the airflow resistance. In a preferred embodiment, the at least one aperture 405 comprises a circular shape. The at least one pleat 404 may be formed by folding the mask frame along fold-lines when the mask frame is in an unassembled state (not shown). The fold-lines may be stiffened regions of the mask frame 401. The stiffened regions are stiffer relative to the remainder of the sheet of material. The fold lines divide the mask frame 401 into several regions. The regions are the top panel 402 and the plurality of side panels 403. The top panel 402 and the side panels 403 are separated by fold lines. The mask frame 401 is provided with a valve 406a provided between a pair of adjacent side panels 403a, 403b. In a non-limiting example as best shown in Figure 11, the mask frame 401 has a plurality of valves 406 each provided between a pair of adjacent side panels 403. The plurality of valves 406 may be formed by folding the mask frame 401. The mask frame 401 may be folded along fold-lines in an unassembled state (not shown). The fold-lines may be stiffened regions of the mask frame 401. The plurality of valves 406 may be normally closed and may open in response to air pressure increasing within the mask body 400. When the plurality of valves open, they may define air passageways for air to escape from the mask body 400. The air passageways may face away from the top panel 402 and may be provided towards a lower margin of the side panels 403. The valves 406 project outwardly from the side panels 403. The valves 406 define an air passageway that allow for air to enter or exit the mask body 400. The air passageways are normally closed as the sides push against one another. However, when the air pressure within the mask body 400 increases the sides move away from one another to form the air passageway. In addition to be used to selectively allow gas to escape from the mask body 400, one or more of the valves 406 can receive a conduit (not shown) for delivering or removing gas from the mask body 400. Conduits may be used during externally assisted ventilation. Advantageously, when the pressure increases within the mask body 400, such as due to the wearer exhaling, the valves 406 open. The air passageways formed by the valves face away from the top panel 402 which means that the exhaled air first hits the top panel 402, or if the top panel 402 has a plurality of apertures 405, the top panel 402 and / or filter 500 before bouncing off into the valve for expulsion via the air passageway. Water and mucus droplets and other large particles expelled by the wearer are likely to be deposited on the top panel 402 and / or filter 500 and only air and gases are expelled to the outside through the valves 406. The filter 500 is formed from a porous material that is suitable to act as a filter 500. Air may be inhaled and exhaled by the wearer through the porous material of the mask body 400. The filter 500 is arranged to trap elements such as microbes and particulates such as dusts and pollens while allowing air exchange with the external environment. Any porous material such as a porous fabric can be used to make the filter. For some advantageous arrangements, the filter has polytetrafluoroethylene (PTFE) and in particular expanded or sintered PTFE or a structurally reinforced composite material based on porous PTFE. Using PTFE or a composite therefore allows filter 500 to be cleaned at a molecular level through capillary action with perfluorocarbons. This allows the filter to be reconditioned and reused. In one example, the filter 500 is formed from a porous PTFE material that is sandwiched between two protective mesh layers. In another example, as best shown in Figure 15 to 16, the filter 500 is a filter 501 pouch 501 formed by at least two or more layers 502 of the porous material, and in this embodiment two layers 502a, 502b of the porous material. The two layers 502a, 502b define at least one cavity 503 therebetween, in particular, one cavity therebetween 503. The filter 500 may be impregnated with an adsorbent configured to adsorb chemical and / or biological agents (not shown). In one embodiment, the filter 500 is impregnated during the fabrication of the filter 500 with the adsorbent configured to adsorb chemical and / or biological agents. In another example, where the filter 500 is a filter pouch 501, the adsorbent configured to adsorb chemical and / or biological agents is located in the at least one cavity therebetween 503. The adsorbent configured to adsorb chemical and / or biological agents may be any suitable material configured for adsorbing chemicals and / or biological agents such as activated charcoal or copper for adsorption of noxious chemicals and / or for killing of microbes. The face mask assembly 300 may be a gas mask for industrial use and / or for use against chemical weapons and / or for use against biological agents. In this embodiment the face mask assembly 300 covers the entire face of the wearer thereby covering the wearer’s eyes. In this embodiment the seal covers the entire face of the wearer thereby covering the wearer’s eyes. Transparent portions are provided in a corresponding location of the mask to the eyes of a wearer for allowing a wearer to see through a face mask of the type which covers the entire face of the wearer. The face mask assembly 300 may further have a harness (not shown) arranged to support the elastic seal 200 on the object. The harness may be coupled to the elastic seal 200. The mask base 207 also has mounting points (not shown) for a harness. The problem of an elastic seal 200 slipping off a domed or other shaped object can be solved by using a harness to support the elastic seal 200 on the object. The harness applies a force to the elastic seal 200 to counter the elastic seal slipping off the sloped surface. The harness applies a force to the elastic seal 200 to prevent the elastic seal 200 from slipping off a sloped surface. The harness may be any means for securing the elastic seal 200 to the object such as straps. For a face mask assembly, the harness may be in the form of straps that secure the harness to the back of the head or ears of the wearer. The harness may secure the elastic seal 200 to the object by stretching the elastic seal 200 backwards in a direction towards the object and thus preventing the elastic seal 200 from slipping off by moving in a direction away from the object. This is referred to as stretching securement. Stretching securement is achieved by the harness pulling the end of the elastic seal facing the object (i.e., the end of the elastic seal that is first inserted over the object). The harness may secure the elastic seal 200 to the object by compressing the elastic seal 200 against the object. This is referred to as compressive securement. Compressive securement is achieved by the harness pulling against the end of the elastic seal 200 that faces away from the object (i.e., the end of the elastic seal that is opposite to the end that is first inserted over the object). The elastic seal 200 has at least one recess 208 sized to accommodate part of the mask body 400, and in particular the mask frame 401. More specifically, and as best shown in the non- limiting example of Figure 11, the mask base 207 of the elastic seal 200 is arranged to accommodate the pleats 404 formed in the side panels 403. A series of recesses 208a configured to accommodate the pleats 404 are formed in the mask base. The recesses 208a configured to accommodate the pleats 404 have a corresponding size and shape to the pleats 404 and in this non-limiting example are in the form of triangular-shaped slots. The mask base 207 is also arranged to accommodate the valves 406. A series of recesses 208b configured to accommodate the valves 406 are formed in the mask base 207. The recesses 208b have a corresponding size and shape to at least part of the valves 406. Figures 13 and 14 show the mask frame 401 secured within the elastic seal 100. The pleats 404 formed in the side panels 403 are received in the recesses 208a. The valves 406 are received in the recesses 208b. The sides of the valves 406 project outwardly and overhang the mask base 207. This means that when the sides move away from one another to open the valve, the air passageway is not covered by the mask base 207. This allows air to be vented outside when the internal pressure within the mask body 400 rises above the external pressure. When the internal pressure is equal or below the external pressure, the sides collapse towards one another under negative pressure and the air passageways are closed. The valves 406 are therefore non-return valves and can be considered as forming duckbill-type valves. Due to the advantageous construction of the mask body 400, the porous material of the filter may have a pore size of less than or equal to 1.0 ^m, less than or equal to 0.7 ^m, less than or equal to 0.5 ^m, or less than or equal to 0.3 ^m. A small pore size, such as a pore size of less than or equal to 0.3 ^m, is particularly effective at blocking bacteria and viruses as well as other particles. The face mask assembly 300 enables acceptable airflow resistance for the wearer even at these small pore sizes. Figures 17 to 22 illustrate a non-limiting example of an embodiment of the elastic seal, generally indicated by reference numeral 600. In this non-limiting embodiment, there is provided an elastic seal 600, the elastic seal having an inner tubular member 601, a bridging portion 602 and an outer tubular member 603. The elastic seal has a mask base 604. In this non-limiting example, the elastic seal 600 has at least one flange 605, and in particular, flanges 605 for preventing slippage of the elastic seal 600. The flanges 605 are configured to grip the user’s face, and in particular grip the user’s face when the elastic seal 600 is in the deployed configuration. In the deployed configuration, the flanges 605 are configured to exert pressure such that the elastic seal 600, and more specifically, the inner tubular member 601 presses against the user’s face. In use, this stops the inner tubular member 601 from rolling up and lifting off the user’s face in use. The flanges 605 may also be protrusions 605 or ridges 605 configured to grip the user’s face. In the non-limiting example shown, the flange 605 is formed from the inner tubular member 601, however other arrangements fall within the scope of this specification. The elastic seal 600 is configured to filter air by electrostatic attraction. Even more specifically, the mask base 604 is configured to filter air by electrostatic attraction. The elastic seal 600 is deformable. In use, deformation of the elastic seal 600 causes the elastic seal 600 to become electrostatically charged or more electrostatically charged. By more electrostatically charged, we mean that the electrostatic potential of the elastic seal 600 is greater than the electrostatic potential prior to deformation. In use, deformation of the elastic seal 600 causes a surface 606 of the elastic seal 600 to become electrostatically charged or more electrostatically charged. The surface 606 of elastic seal interfaces with inhaled air and / or exhaled air and / or surrounding environmental air. By more electrostatically charged, we mean that the electrostatic potential of the surface 606 of the elastic seal 600 is greater than the electrostatic potential of said surface 606 prior to deformation and is therefore configured to exert a greater electrostatic force. We also mean that the electrostatic potential measured on said surface 606 of the elastic seal 600 is greater than the electrostatic potential measured on said surface 606 prior to deformation. The elastic seal 600 is elastically deformable. The mask base 604 is elastically deformable. In use, elastic deformation of the elastic seal 600 causes the surface 606 of the elastic seal 600 to become electrostatically charged or more electrostatically charged. By more electrostatically charged, we mean that the electrostatic potential of the surface 606 of the elastic seal 600 is greater than the electrostatic potential of said surface 606 prior to elastic deformation and is therefore configured to exert a greater electrostatic force. We also mean that the electrostatic potential measured on said surface 606 of the elastic seal 600 is greater than the electrostatic potential measured on said surface 606 prior to elastic deformation. The elastic seal 600 is rechargeable. The surface 606 of the elastic seal 600 is rechargeable. By rechargeable, we mean that the elastic seal 600 is configured to be recharged with electrostatic charges. In use, recharging of the elastic seal 600 also means that the electrostatic potential of the elastic seal 600 is greater, such that the elastic seal 600 is configured to exert a greater electrostatic force to electrostatically capture elements such as microbes and particulates such as dusts and pollens. It will therefore also be readily understood by the skilled person that the face mask assembly is therefore rechargeable. The elastic seal 600 is rechargeable by deformation of the elastic seal 600. The surface 606 of the elastic seal 600 is rechargeable by deformation of the elastic seal 600. The elastic seal 600 is rechargeable by elastic deformation of the elastic seal 600. The surface of the elastic seal 600 is rechargeable by elastic deformation of the surface 606 of the elastic seal 600. The elastic seal 600 is rechargeable by repeated elastic deformation of the elastic seal. 600. The surface 606 of the elastic seal 600 is rechargeable by repeated elastic deformation of the surface 606 of the elastic seal 600. The elastic seal 600 is rechargeable by stretching and / or relaxation, and in particular, repeated stretching and / or relaxation of the elastic seal 600. Ideally, the surface 606 of the elastic seal 600 is rechargeable by stretching and / or relaxation, and in particular, repeated stretching and / or relaxation of the surface 606 of the elastic seal 600. The elastic seal 600 is configured to maintain an electrostatic charge or become more electrostatically charged as the mask is repeatedly used. The elastic seal 600 is rechargeable by a user of the mask assembly. Yet even more specifically, the surface 606 of the elastic seal 600 is rechargeable by a user of the face mask assembly. It is known that electrostatic charges could be induced on a surface by friction (triboelectricity) and mechanical stress (piezoelectricity). More recently, it has also been reported that elastomers may become electrostatically charged from stretching and / or relaxation in humid environments [see, e.g. Burgo, TAL et. al, ACS Omega, 2017, 2, 12: 8940–8947]. The elastic seal 600 has a plurality of pores 607. Even more specifically, the mask base 604 has the plurality of pores 607. In a non-limiting example of the embodiment as best shown in Figures 21 and 22, the plurality of pores 607 is formed from a plurality of porous layers 608, and in particular two porous layers 608a, 608b. The plurality of pores 607 is configured to enable passage of inhaled air from the environment and exhalation of air from the wearer to the environment. In the non- limiting example of the embodiment as best shown in Figures 21 and 22, each porous layer 608a, 608b has a plurality of air channels 609. The plurality of air channels 609 of one porous layer 608 interconnect with an adjacent porous layer 608 or adjacent porous layers 608 to form the plurality of pores 607. In use, the elastic seal 600 is configured to electrostatically capture elements such as microbes and particulates such as dusts and pollens. The elements and particulates may also be collectively referred to an undesirable matter. The mask base 604 is configured to electrostatically capture elements such as microbes and particulates such as dusts and pollens. The surface 606 of the elastic seal 600 is configured to electrostatically capture elements such as microbes and particulates such as dusts and pollens. The plurality of pores 607 is configured to electrostatically capture elements such as microbes and particulates such as dusts and pollens. In use, the elastic seal 600 is configured to electrostatically capture elements such as microbes and particulates such as dusts and pollens exhaled by the wearer and inhaled by the wearer. In use, the mask base 604 is configured to electrostatically capture elements such as microbes and particulates such as dusts and pollens exhaled by the wearer and inhaled by the wearer. The surface 606 of the elastic seal 600 is configured to electrostatically capture elements such as microbes and particulates such as dusts and pollens exhaled by the wearer and inhaled by the wearer. The plurality of pores 607 is configured to electrostatically capture elements such as microbes and particulates such as dusts and pollens exhaled by the wearer and inhaled by the wearer. The plurality of pores 607 is deformable. The plurality of pores 607 is configured to become electrostatically charged or more electrostatically charged during deformation of the plurality of pores 607. The plurality of pores 607 is configured to become electrostatically charged or more electrostatically charged by elastic deformation of the plurality of pores 607. The plurality of pores 607 is configured to become electrostatically charged or more electrostatically charged by repeated elastic deformation of the plurality of pores 607. The plurality of pores 607 is located within the elastic seal 600, and more specifically the mask base 604 of the elastic seal, although it will be readily understood to skilled person that other arrangements fall within the scope of the patent specification. The plurality of pores 607 is located within a part of the elastic seal 600, and more specifically the mask base 604 of the elastic seal. In the non-limiting example of the embodiment shown, the plurality of pores 607 is homogeneously formed from the elastic seal 600, and particularly the mask base 604. In use, the plurality of pores 607 ultimately reduces the weight of the elastic seal 600 and thus the face mask assembly. This lessens the strain on the wearer of the face mask assembly. In use, the plurality of pores 607 also aids deformation of the elastic seal 600 and thus recharging of the elastic seal. The plurality of pores 607 has an adjustable cross-sectional area. The plurality of pores 607 has a non-linear cross-sectional area across the length of the plurality of pores 607. The cross-sectional area of the plurality of pores 607 is adjusted in a parallel direction to the airstream. The airstream may include incoming air inhaled by the wearer of the face mask assembly, or exhaled air that is exhaled by the wearer of the face mask assembly. In use, the adjusted cross- sectional area increases the surface area of silicone an airstream must pass through, thereby maximising electrostatic capture. The elastic seal 600 is cleanable. The plurality of pores 607 is cleanable. The elastic seal 600 is cleanable by washing the elastic seal 600. More specifically, the elastic seal 600 is cleanable by washing the elastic seal 600 to remove any electrostatically attracted matter and / or to sterilise the elastic seal 600. The elastic seal 600 may be washed using any suitable washing fluid (not shown), such as a fluid having water and / or soap and / or alcohol to remove any electrostatically attracted matter and / or to sterilise the elastic seal. A non-limiting example of an embodiment of the face mask assembly, generally indicated by reference numeral 700, is illustrated in Figures 23 and 24. In this non-limiting example, the face mask assembly 700 has an elastic seal 600 and a mask body 800, the elastic seal 600 having an inner tubular member 601, a bridging portion 602 and an outer tubular member 603. The elastic seal 600 has a mask base 604. The elastic seal 600 shown in this non-limiting example is the same elastic seal 600 as described above in relation to Figures 17 to 22. The mask body 800 has a filter 900 and a mask frame 1000, as best illustrated in the non-limiting examples shown in Figures 25 to 33. In this non-limiting example, the face mask assembly 700 also has a layer of activated carbon for adsorbing chemicals and / or biological agents 1100. This layer of activated carbon 1100 is separate to, and works in conjunction with, the filter 900 to filter air. In the non-limiting example of the embodiment shown, the layer of activated carbon 1100 is disposed between the mask base 604 and the mask body 800 although it will be readily understood to the skilled person that other arrangements fall within the scope of the present invention. In a non-limiting example of the embodiment shown in Figures 21 and 22, the face mask assembly 700, and in particular the elastic seal 600 has an expandable seal 1120 for securing at least part of or all of the mask body 800 and / or at least one layer of activated carbon for adsorbing chemicals and / or biological agents 1100. The expandable seal 1120 may also be referred to as an expandable sealing portion 1120. In this non-limiting example of the embodiment, the expandable seal 1120 secures all of the mask body 800 and the layer of activated carbon for adsorbing chemicals and / or biological agents 1100, although other arrangements fall within the scope of present invention. The expandable seal 1120 is homogeneously formed from the elastic seal 600. The expandable seal 1120 is homogeneously formed from the mask base 604. The expandable seal 1120 is located in the mask base 604. The expandable seal 1120 has a recess configured to receive at least part of or all of the mask body and / or at least one layer of activated carbon for adsorbing chemicals and / or biological agents 1121. The expandable seal 1120 is reversibly expandable between a rest state and an expanded state. The expandable seal 1120 is expandable from the rest state to the expanded state by force. The expandable seal 1120 is expandable from the rest state to the expanded state by stretching. The expandable seal 1120 is reversibly expandable from the rest state to the expanded state by force. The expandable seal 1120 contracts upon removal of the force. The expandable seal 1120 relaxes upon removal of the force. The expandable seal 1120 is elastically deformable. In the rest state, as best shown in a non-limiting example of the embodiment shown in Figure 21, the recess configured to receive at least part of or all of the mask body and / or at least one layer of activated carbon for adsorbing chemicals and / or biological agents 1121 has an internal volume. In the expanded state, the recess configured to receive at least part of or all of the mask body and / or at least one layer of activated carbon for adsorbing chemicals and / or biological agents 1121 has an internal volume that is larger than the internal volume of said recess 1121 within the rest state. In the non-limiting example of the embodiment as best shown in Figures 23 and 24, the mask body 800 and the at least one layer of activated carbon for adsorbing chemicals and / or biological agents 1100 is secured, and in particular, detachably secured within the expandable seal 1120. The expandable seal 1120 is configured to secure the mask body 800 and / or at least one layer of activated carbon for adsorbing chemicals and / or biological agents 1121 by expanding the expandable seal 1120 to the expanded state, inserting a part of or all of the mask body 800 and / or at least one layer of activated carbon for adsorbing chemicals and / or biological agents 1100, and contracting said expandable seal 1120 such that it seals around or against the mask body 800 and / or at least one layer of activated carbon for adsorbing chemicals and / or biological agents 1100. The expandable seal 1120 is configured to secure the mask body 800 and / or at least one layer of activated carbon for adsorbing chemicals and / or biological agents 1100 by expanding the expandable seal 1120 to the expanded state, inserting a part of or all of the mask body 800 and / or at least one layer of activated carbon for adsorbing chemicals and / or biological agents 1100, and removing the force such that the expandable seal 1120 urges towards the rest state such that it seals around the part of or all of the mask body 800 inserted and / or at least one layer of activated carbon for adsorbing chemicals and / or biological agents 1100. In Figures 25 to 27, there is shown a non-limiting example of an embodiment of the mask frame, generally indicated by reference numeral 1000. The mask frame 1000 has a pleated frame 1001. The mask frame 1000 has at least one pleat 1002, and in particular, a plurality of pleats 1002. In the non-limiting example of the embodiment shown, the pleated frame 1001 is a fully pleated frame 1001. The plurality of pleats 1002 forms the pleated frame 1001. The mask frame 1000 is configured to provide structural support and flexibility to the mask body 800. The mask frame 1000 is formed from a material configured to provide structural support and flexibility. The material configured to provide structural support and flexibility may also be known as a semi-rigid material. In use, the use of a material configured to provide structural support and flexibility enables the mask frame 1000 to retain the shape of pleated frame 1001 whilst also enabling the frame 1000 to adapt to shape changes in the user’s face during usage of the face mask assembly 700. The mask frame 1000 is formed from a material configured to provide structural support and flexibility such as mylar. The mask frame 1000 is formed from a single folded sheet of material configured to provide structural support and flexibility without any joints formed by welding, sewing, adhesives, or other attachment methods. This simplifies the construction of the mask frame 1000 as separate elements are not required to be attached together to form the mask frame 1000. The absence of joints that require attachment reduces the risk of leakage and simplifies the manufacturing process. The mask frame 1000 has at least one aperture configurable to enable the user to breathe easier by lowering the airflow resistance 1004. In this embodiment, the at least one aperture configurable to enable the user to breathe easier by lowering the airflow resistance 1004 is located on the plurality of pleats 1002. The at least one aperture configurable to enable the user to breathe easier by lowering the airflow resistance 1004 is located on the pleated frame 1001. In the non-limiting example of the embodiment shown, the at least one aperture configured to enable the user to breathe easier by lowering the airflow resistance 1004 has a circular shape. In Figures 28 to 30, there is shown a non-limiting example of an embodiment of the filter, generally indicated by reference numeral 900. The filter 900 is pleatable. By pleatable, we mean the filter 900 is capable of being pleated. The filter 900 is a pleated sheet 901. In the non-limiting example of the embodiment shown, the filter 900 is a fully pleated sheet 901. The filter 900 is pleatable to form a pleated filter 901. The filter 900 is pleatable by folding to form the pleated filter 901, and in particular a fully pleated filter 901. In use, pleating of the filter 900 increases the surface area of the filter 900 available for filtration without increasing the mask volume. This means that the filter 900 provides a lower airflow resistance. Breathing is easier for the wearer as there is lower airflow resistance and hence lower inspiratory pressure is required. Moreover, the breathing is more energy efficient as there is less dead space to ventilate for the wearer. In the non-limiting example of the embodiment shown, the filter 900 is a membrane filter 901. The membrane filter 901 is pleated to form a pleated membrane 901, and in particular, is pleated to form a fully pleated membrane 901. The membrane 901 is pleated by folding of the membrane 901 to form the pleated membrane 901. In use, the pleating of the filter 900, and more specifically, the membrane 901 reduces the effective pore size exposed to particles carried by convection in the airflow. Figures 34A to 34D illustrates this phenomenon in more detail. In Figure 34A, there is shown one half of a folded at least one pleat 902 of the pleated filter 901. In Figure 34A, there is shown a normal-to-face view of a first face 903a of at least one pleat 902 of the pleated filter 901. The face 903a of the at least one pleat 902 of the pleated filter 901 has a pore 904, with an exposed width ‘a’. Figure 34B shows a three-dimensional perspective view of the at least one pleat 902 of the pleated mask filter 901. The at least one pleat 902 has a crease 905, a first face 903a and a second face 903b. Airflow is travelling in the normal direction to the crease 905 in this example as may be the case, for example, during inhalation by the wearer of the face mask assembly 700. In Figure 34C, there is shown a normal-to-crease view of at least one pleat 902 of the pleated filter 901. The normal- to-crease view is also viewed in alignment with the airflow direction, i.e. airflow is flowing towards the crease 905 and approaching the crease 905 of the at least one pleat 902. The pore 904 now has an exposed width ‘b’ in the normal-to-crease direction. The exposed width ‘b’ is smaller than the exposed width ‘a’. This is illustrated in Figure 34D, wherein, assuming each half of a pleat makes an angle of ^ with respect to the direction of the airflow, the effective pore size seen by particles carried by convection will be reduced by sin ^ < 1. This means that pore sizes larger than the diameter of the smallest particles required to be trapped may be used whilst also maintaining high filtration efficiency. Accordingly, this also reduces the airflow resistance whilst also maintaining high filtration efficiency. The filter 900 is formed from a porous material that is suitable to act as a filter 900. Air may be inhaled and exhaled by the wearer through the porous material of the mask body 800. The filter 900 is arranged to trap elements such as microbes and particulates such as dusts and pollens while allowing air exchange with the external environment. Any porous material such as a porous fabric can be used to make the filter 900, however in an advantageous arrangement, the filter is formed from polytetrafluoroethylene (PTFE) and in particular expanded PTFE. The filter 900 is cleanable. The filter 900 is cleanable such that the filter 900 may be re- used. The filter 900 is cleanable and re-useable. The filter 900 is cleanable using a fluid configured to wet the filter (not shown). By wet the filter 900, we mean that said fluid configured to wet the filter 900 is configured to adhere to and is able to penetrate the filter 900 upon contact with the filter 900. In an advantageous arrangement, wherein the filter 900 is formed from expanded PTFE and is a membrane filter 901, said filter 900 is cleanable by rubbing or washing the filter 900 with a jet (not shown), wherein the jet uses the fluid configured to wet the filter 900. Advantageously, the cleaning of the filter 900 in such a manner dislodges fine particles embedded in the filter 900 from usage of the face mask assembly 700. In this advantageous arrangement, the fluid configured to wet the filter 900 contains an alcohol, such as isopropanol. As best shown in the non-limiting examples of the embodiment illustrated in Figures 31 to 32, there is shown a mask body, as generally indicated by reference numeral 800. The mask body 800 is pleated. In the non-limiting example shown, all the mask frame 1000 and all of the filter 900 is pleated, although other arrangements and configurations fall within the scope of the present invention. The mask frame 1000 and the filter 900 is fully pleated. By fully pleated, we mean that the mask frame 1000 and the filter 900 is pleated across the entire length and entire width of the mask frame 1000 and the filter means 900. In the non-limiting example of the embodiment shown, the pleated mask frame 1000 and the pleated filter 900 are configured to engage with each other. In the arrangement shown, the pleated mask frame 1000 is secured to the pleated filter 900 using at least one tie 801, and in particular, two ties 801a, 801b. In this arrangement, the at least one tie 801 is received by a plurality of mask frame apertures 1003 configured to receive the at least one tie 801 and a plurality of filter means apertures 910 configured to receive the at least one tie 801. In Figures 35A to 35C, there is shown a non-limiting example of an absorbent for absorbing fluids, generally indicated by reference numeral 1150. In this example, the absorbent is an adhesive dressing 1151. The face mask assembly may have the adhesive dressing 1151. The absorbent for absorbing fluids 1150 is configured to absorb fluids secreted by a user of the mask. The absorbent for absorbing fluids 1150 is configured to absorb moisture and oil, however other absorbents, such as those configured to absorb moisture or oil, fall within the scope of the present disclosure. The absorbent for absorbing fluids 1150 is configured to prevent slippage of the face mask assembly by absorbing fluids secreted by a user of the face mask assembly. The absorbent for absorbing fluids 1150 is configured to capture fluids secreted by the user of the face mask assembly, such as oil and / or sweat for example. The absorbent for absorbing fluids 1150 is configured to capture fluids secreted and / or exhaled by the user of the face mask assembly. In use, this enables the face mask assembly, and more specifically, the elastic seal to stay affixed to the face of the user in use without slippage over time due to accumulation of moisture and / or sweat from use. In the non-limiting example shown in Figures 35A to 35C, the absorbent for absorbing fluids 1150 can adhere to the skin of the user. In this non-limiting example, the absorbent for absorbing fluids 1150 can be interposed between the elastic seal and the skin of the user. It will be readily understood that other absorbents and / or arrangements, outside of the absorbent shown in Figure 35A to C, for absorbing fluids fall within the scope of the present disclosure, for example the use of a desiccant such as silica gel (not shown). The desiccant can be located within the internal volume defined between the mask body and the wearer. The desiccant is configured to capture condensation locatable within the internal volume defined between the mask body and the wearer. In some examples, the face mask assembly has the adhesive dressing interposed between the elastic seal and the skin of the user, as well as silica gel located within the internal volume defined between the mask body and the wearer. The adhesive dressing 1151 is configured to prevent skin abrasion during usage of the face mask assembly. The adhesive dressing 1151 may be a hydrocolloid dressing. In use, the usage of a hydrocolloid dressing also prevents the user from suffering from an allergic reaction. The adhesive dressing 1151 is configured to capture moisture and / or oil. In use, the adhesive dressing 1151 is configured to prevent or reduce contact between the elastic seal and the skin of the user. In use, this prevents moisture and oil from accumulating and prevents slippage of the face mask assembly, and particularly the elastic seal. As best shown in the non-limiting examples of Figure 35A and 35B, the adhesive dressing 1151 is gridded radially and angularly 1152. The adhesive dressing 1151 can be cut, as best shown in Figure 35B. The adhesive dressing 1151 can be cut to the size and shape of the user’s nose-mouth region. In Figure 35C, there is shown the adhesive dressing 1151 rolled into a truncated cone 1153. The adhesive dressing 1151 may then be applied to the user’s face, prior to application of the elastic seal to the user’s face. Now generally referring to Figures 36 to 50, there is shown another non-limiting example of a face mask assembly 1200 and parts thereof, such as an elastic seal 1300 and a mask body 1400. In Figures 36 and 37, there is shown a further non-limiting example of a face mask assembly, generally indicated by reference numeral 1200. The face mask assembly 1200, in accordance with the other non-limiting examples previously described, comprises an elastic seal 1300 and a mask body 1400. The elastic seal 1300 comprises an inner tubular member 1301, a bridging portion 1302 and an outer tubular member 1303. In the non-limiting example shown, the face mask assembly 1200 may be useable as a CPAP face mask assembly 1200. Additionally, the face mask assembly 1200 may be equally applied and advantageous in other ventilation applications, including other non-invasive ventilation applications such as Bilevel Positive Airway Pressure (BiPAP) and minimally invasive ventilation applications which may use oropharyngeal or nasopharyngeal airways for mechanical ventilation of the lungs. The mask body 1400 is integrated into the elastic seal 1300, as will later be described. The elastic seal 1300 operates in the same manner as the other non-limiting examples of the elastic seal described above. More specifically, the elastic seal 1300, and in particular, the inner tubular member 1301 is invertible from a rest configuration to a deployed configuration so as to form a sealing perimeter 1317 around the nose and mouth of a user of the face mask assembly 1200. The elastic seal 1300, in forming the sealing perimeter 1317, also may seal around the chin of a user and the elastic seal 1300 therefore has an integrated chinstrap function built therein. As described previously, the face mask assembly 1200 and in particular, the elastic seal 1300 is readily cleanable and may be washed using any suitable washing fluid such as a fluid having water and / or soap and / or alcohol to remove any electrostatically attracted matter and / or to sterilise the elastic seal 1300. As the mask body 1400 is integrated in the elastic seal 1300 in this embodiment, there is no risk of alcoholic or organic solvent-based cleaning agents causing the detachment of these two components. As shown in Figures 36 and 37, the face mask assembly has a harness 1201 arranged to support the elastic seal 1300 on an object e.g. a user’s face. Whilst previous examples described describe a harness being connected to mounting points located on the elastic seal e.g. the mask base, the harness 1201 as shown in this non-limiting example is coupled indirectly to the mask body 1400 via one or more coupling loops (four shown) 1202. It will be appreciated however, that the harness 1201 as shown may instead be coupled directly and / or indirectly to the elastic seal 1300 instead, or the harness 1201 could be coupled directly and / or indirectly to both the elastic seal 1300 and the mask body 1400. The harness as shown in Figures 36 and 37 has two straps, 1203a, 1203b. The harness 1201 may also be referred to as headgear 1201. In other arrangements, however, the harness 1201 may have a single strap, or more than two straps. One of the straps 1203a is configured, in use, to be a top strap 1203a. By top strap, it will be understood that this strap 1203a is situated, in use, towards the top of the head of user. The other strap 1203b, is configured, in use to be a bottom strap 1203b. It will be understood bottom strap 1203b refers to the strap being situated, in use, below the top strap 1203a. As shown in Figures 36 and 37, the straps 1203a, 1203b are independent of each other. In other arrangements, however, as best shown in Figure 38, the top strap 1203a may optionally be connected to the bottom strap 1203b via at least one interconnecting strap 1216. The interconnecting strap 1216 interconnects the top strap 1203a and 1203b using a hook-and-loop fastening arrangement in the non-limiting example shown. The harness 1201 may also be coupled directly and / or indirectly to the mask body 1400. In some embodiments, the straps 1203a, 1203b may comprise a single-layered strap. However, in other embodiments, as best shown in Figure 39, each strap 1203a, 1203b may comprise a plurality of strap layers 1204, 1205, 1206. Each strap 1203a, 1203b is securable directly and / or indirectly to the elastic seal 1300 and / or mask body 1400. As shown in the non-limiting example shown in Figures 36 and 37, each strap is secured the mask body 1400 integrated into the elastic seal 1300, and in particular, secured indirectly to one or more attachment means 1403 in the form of attachment loops 1403 forming part of the mask body 1400 integrated into the elastic seal 1300. Each strap 1203a, 1203b as shown in this non-limiting example is secured indirectly to two of attachment means 1403 of the mask body 1400 integrated into elastic seal 1300 via intermediary coupling members 1202, with each strap 1203a, 1203b, being secured directly to the intermediary coupling members 1202. In more detail each strap 1203a, 1203b is securable directly and / or indirectly to the elastic seal and / or mask body via at least one securing means 1207 e.g at least one securing loop 1207 for securing the harness 1201 to the elastic seal 1300 and / or mask body 1400. In the non-limiting example of the face mask assembly 1200 shown in Figure 36 and Figure 37, each end of each strap 1203a, 1203b is secured via a securing loop 1207 that is directly coupled to an intermediary coupling member 1202. Each strap 1203, 1203b is adjustable so as to control the force with which the elastic seal 1300 is pulled onto the face of a user of the face mask assembly 1200. In more detail, each strap 1203a, 1203b is adjustable so as to control the force with which the elastic seal 1300 is pulled onto the face of a user via adjustment of the securing loop(s) 1207. The, or each, securing loop 1207 as shown is formed from use of at least one fastener 1204. In this non-limiting example, the fastener 1204 comprise a hook-and-loop fastener 1205. It will be appreciated however, that the securing means need be formed via a hook-and-loop fastener, and each securing means may instead comprise other securing mechanisms such as clips (e.g. magnetic clips, compressible buckle clips), rigid plastic pillars and slots for example. The hook-and-loop fastener 1204 may comprise a hook-and-loop fastening layer 1204. The hook-and-loop fastening layer 1204 may form at least one layer of the plurality of strap layers 1204, 1205, 1206 and accordingly, this layer 1204 may also be referred to as the securing layer 1204. Alternatively, in embodiments where each strap is a single-layered strap, the single-layered strap may be the securing layer 1204. In more detail, the securing layer 1204 comprises a first securing layer surface 1208, one or more hooking members 1209 and a second securing layer surface 1210. The first securing layer surface 1208 comprises a loop portion 1211 located on at least part of, or all of, the first securing layer surface 1208. The second securing layer surface 1210 may be a non-loop layer surface 1210. By non-loop layer surface 1210, it will be understood that this surface 1210 does not comprise loops for engaging with the hooking means 1209. Each strap 1203a, 1203b may comprise a first hooking member 1209a located at a first end of each strap 1203a, 1203b, and a second hooking member 1209b located at a second end of each strap 1203a, 1203b, said second end being distal to the first end of each strap 1203a, 1203b, as best illustrated in Figure 38. The hooking member 1209 may comprise a hooking patch 1209 for fastening to the loop portion 1211 of the first securing layer surface 1208. The hooking patch 1209 may comprise a first hooking surface 1212 for fastening to the loop portion 1208, and a second hooking surface 1213 for fastening to the loop portion 1208. The hooking patch 1209 is fastenable, and more preferably, detachably fastenable to a first part of the loop portion 1208 via the first hooking surface 1212. The fastened hooking patch 1209 that is fastened on the first part of the loop portion 1208 is fastenable, and more preferably, detachably fastenable to a second part of the loop portion 1211, via the second hooking surface 1213 so as to form the securing loop 1207. Beneficially, the ability to detachably fasten the hooking patch 1209 enables a user of the face mask assembly 1200 to control the force with which the elastic seal 1300 is pulled onto an object, such as the face of a wearer of the face mask assembly 1200. In the non-limiting example as best shown in Figure 39, wherein the strap comprises a plurality of layers 1204,1205,1206, each strap 1203a, 1203b may comprise a backing layer 1205 as best shown in Figure 39. The backing layer 1205 may comprise a first backing layer surface 1214 and a second backing layer surface 1215. The backing layer 1205 is an inelastic layer 1205. The backing layer 1205 is a flexible layer. The backing layer 1205, and in particular, the first backing layer surface 1214 is configured to engage with the second securing layer surface 1210 of the securing layer 1204. In use, where the backing layer 1205 is inelastic and flexible, the backing layer 1205 is configured to prevent narrowing and twisting of the strap 1203a,1203b so as to prevent a twisted strap abrasively rubbing against the face of a user of the face mask assembly 1200. In embodiments where the straps 1203a,1203b comprise a plurality of strap layers 1204,1205,1206, the straps may comprise an elastic strap layer 1206, as best illustrated in Figure 39. The elastic strap layer 1206 may be formed from silicone and may be referred to as a silicone strap layer 1206. The elastic strap layer 1206 is configured, in use, to stretch in a transverse and longitudinal direction. Figure 43 illustrates this in further detail in relation to usage of each strap 1203a, 1203b comprising a plurality of strap layers 1204,1205,1206, and in particular, to the function of the elastic layer 1206. As shown, a securing loop 1207 has been formed in the strap shown and as previously described. In use, application of a tension force 1218 (for example when each strap 1203a,1203b is applied in use on the head of a user of the face mask assembly 1200 and is thus being stretched) also generates a normal pressure force 1217 that is perpendicular to the direction of the tension force 1218. Due to the usage of an elastic layer 1206, and in particular, a silicone layer 1206, the silicone layer 1206 is configurable, in use, to spread transversely and longitudinally. In use, this distributes the normal force 1217 over a larger area by increasing the contact area of the silicone layer 1206 with the skin, thereby reducing the pressure exerted on the face of a wearer of the face mask assembly 1200, which thus mitigates any discomfort and potential skin damage through prolonged use. This is particularly important for applications, such as CPAP, where a user of the face mask assembly 1200 may be using the mask for prolonged periods of time, and so implementation of the elastic layer 1206 mitigates any discomfort which may arise from prolonged usage of any CPAP mask. The silicone strap layer 1206 is also functionable as a non-slip strap layer 1206. In use, the usage of a silicone, when in contact with skin, results in a high coefficient of friction, thereby enabling the silicone strap layer 1206 to function as a non-slip layer 1206. Figure 44 provides further detail in relation to this property. It will be understood and appreciated by the skilled person that, by having a high coefficient of friction, this refers to the coefficient of friction associated with contact of the silicone layer 1206 and the face of a wearer of the face mask assembly 1200. In use, any tangential movement, may be, in turn, absorbed by shear stress within the strap 1203a, 1203b, and in particular, the silicone strap layer 1206, which prevents transmission of tangential movement of the each strap 1203a, 1203b relative to the skin of a user of the face mask assembly 1200. In use, this beneficially protects against skin abrasion that may otherwise occur in absence of the silicone strap layer 1206. Referring now generally to Figures 45 to 50, there is shown the elastic seal 1300 of the CPAP face mask assembly 1200, wherein a mask body 1400 is integrated into the elastic seal 1300. By being integrated into the elastic seal 1300, it will be appreciated that the mask body 1400 is secured within the elastic seal 1300. However, in other embodiments of the face mask assembly 1200, the mask body may be separate to and securable to or within the elastic seal. In these embodiments, where the mask body may be formed as a singular mask body comprising a mask frame and attachment means for coupling the harness of the face mask assembly thereto, or could also be formed as a modular mask body, wherein the mask body comprises a first mask frame member and a second mask frame member, with at least one of the mask frame member having attachment means for attaching a harness thereto. As shown best shown in Figure 45, there are one or more coupling loops (four shown) 1202 for indirectly coupling each strap 1203a, 1203b of the harness 1201 to the mask body 1400, and in particular, to the attachment means 1403 extending from the integrated mask frame 1401. Each coupling loop 1202 is couplable to a respective securing loop 1207 of the straps 1203a, 1203b of the harness 1201. The coupling loops 1202 function as intermediary coupling members 1202 for indirectly coupling the harness 1201 to the mask body 1400, and in particular to the one or more attachment means 1403 of the integrated mask frame 1401 of the mask body 1400, as will later be described. As shown, the coupling loops 1202 are circular coupling loops 1202, however, it will be appreciated that other configurations and coupling mechanism e.g. clips could be used for coupling the harness 1201 to the integrated mask frame 1401. In use, the one or more intermediary coupling members 1202 are configured to enable angular adjustment of the harness 1201. In particular, in embodiments wherein each strap 1203a, 1203b comprises a fastener 1204 that is operable, in use, to form one or more securing loops 1207, the securing loop 1207 may be securable to a respective coupling loop 1202 and is slidable about the respective loop 1202. Beneficially, this provides the face mask assembly 1200 with the ability to accommodate different three-dimensional shapes associated with users of the face mask assembly 1200. Yet further beneficially, the intermediary coupling members 1202 being functionable as angular adjustment means for angularly adjusting the harness 1201 relative to the face of a user of the face mask assembly 1200, in combination with the adjustability of each strap 1203a, 1203b so as to control the force with which the elastic seal 1300 is pulled onto the face of a wearer of the face mask assembly 1200 confers, on the face mask assembly 1200, substantial flexibility as to what three-dimensional shapes may be accommodated using the face mask assembly 1200. This ensures that a single harness 1201 may be used to fit multiple wearers of the face mask assembly 1200 having different head sizes and shapes. Furthermore, the intermediary coupling members 1202 are arranged to have a diameter that enables a user of the face mask assembly 1200 to easily secure one or more securing loops 1207 of the harness thereto. In more detail, for users of the face mask assembly 1200 who have, for example, reduced manual dexterity or eyesight, the coupling loops 1202 are arranged to protrude from the integrated mask frame 1401 so as to enable a user to readily fasten the harness 1201 thereto. In use, the coupling loops 1202 are arranged to be distal to the face of the user of the face mask assembly 1200, so as to prevent the coupling loops from causing discomfort to the face of the user of the face mask assembly 1200. The elastic seal 1300, and in particular the mask base 1304 of the elastic seal 1300 and / or the mask body 1400 may be connectible to a CPAP machine. In the non-limiting example shown, the mask body 1400 comprises a mask frame 1401 that is integrally formed with the elastic seal 1300, and, in particular, integrally formed with the mask base 1304 of the elastic seal 1300. The mask base 1304 has a mask base aperture 1305 for securing objects therein and / or thereto. In embodiments as previously described, the mask base typically has a mask base aperture for securing an object for example the mask frame 400, as shown in the embodiment in Figure 11, or a mask body 800, as shown in the embodiment in Figure 23. However, in the embodiment as best shown in Figures 45 to 50, the mask base aperture 1305 may be arranged to secure a connecting means (not shown), such as a vent ring, for connecting a CPAP machine to the face mask assembly 1200. The mask base aperture 1305 may include a stop member to prevent or mitigate slippage of the vent ring out of the mask base aperture 1305. The mask body 1400, and particularly the mask frame 1401, comprises a mask frame aperture 1402. The mask frame aperture 1402 has a diameter greater than the diameter of the mask base aperture 1305. In use, the integrated mask frame 1401 is arranged to securely hold the connecting means in place so as to prevent the connecting means from inadvertently slipping out of the face mask assembly 1200. The integrated mask frame provides support to the mask base aperture 1305, so as to prevent the connecting means from inadvertently slipping out of the face mask assembly 1200. In other examples not shown, however, where, for example, the mask body is separate to the elastic seal and not integrated into it, the mask body itself be arranged to directly secure a connecting means for connecting a CPAP machine to the face mask assembly 1200. In the non-limiting example shown, the mask body 1400 has one or more attachment means 1403 extending from the integrated mask frame 1401. In more detail, each attachment means 1403 extends through a corresponding slit formed within the mask base 1304 for protrusion of the attachment means 1403 therethrough. Each attachment means 1403 is arranged for a harness 1201 to be coupled directly and / or indirectly (i.e. via the coupling loops 1202) thereto, as previously described. As shown, each attachment means 1403 comprises an attachment loop 1403. In use, in embodiments wherein the, or each, strap 1203a, 1203b of the harness 1201 is coupled directly and / or indirectly to the one or more attachment loops 1403, each loop 1403 is rotatable, in use, about a first orthogonal axis, said first orthogonal axis being the longitudinal axis of the attachment loop 1403, a second orthogonal axis and a third orthogonal axis, wherein rotation about the first orthogonal axis provides each strap 1203a, 1203b directly and / or indirectly coupled to a respective attachment loop 1403 with an added torsional component to the tangential pull exerted by the, or each, strap 1203a, 1203b. This enables the face mask assembly 1200 to accommodate different head pull directions associated with users having different head shapes and sizes. The integrated mask frame 1401 and the attachment loops 1403 are homogenously formed as the mask body 1400. The mask body 1400 is formed from a flexible, but non- stretchable material such as mylar. In other non-limiting examples, however, the attachment means forming part of the mask body may be attachable to the mask frame, or in other examples, where the mask body is a modular mask body comprising a first mask frame member and a second mask frame member, the attachment means may be homogenously formed as or attached to only one of the mask frame members. To integrate the mask body 1400 into the elastic seal 1300, the mask body 1400 is integrated into elastic seal 1300 by over-moulding. Beneficially, this obviates any requirement for usage of an adhesive, meaning that the face mask assembly may be readily cleaned with water and common cleaning agents such as alcohols / alcoholic mixtures without any risk of the elastic seal 1300 and mask body 1400 separating. In other examples, however, the mask body 1400 could be secured to or within the elastic seal 1300 e.g. by usage of the expandable seal mechanism 1102 as previously described. The mask body 1400 has a plane of symmetry in a first plane. The first plane is a central plane that is perpendicular to the planarity of the mask frame 1401. The attachment loops 1403 on a first side of the plane of symmetry have a corresponding, symmetrically arranged attachment loop 1403 arranged on the second side of the plane of symmetry, as best shown in Figure 36. In use, this ensures that the pull force exerted on the elastic seal 1300 and thus onto the face of the user of the face mask assembly 1200 via the tension generated in the harness 1201 is balanced. The elastic seal 1300 of the CPAP face mask assembly 1200, and in particular, the inner tubular member 1301 comprises flanges 1306 for preventing slippage of the elastic seal 1300, the flanges 1306 being configurable to grip an object e.g. a user’s face. The flanges function in the same manner as the flanges described previously (e.g. flanges 605). The flanges 1306 are located on the first tubular surface 1307 of the inner tubular member 1301. When the elastic seal 1300 is in the deployed configuration, the flanges 1306 are configurable to exert pressure such that the elastic seal 1300, and more specifically, the inner tubular member 1301 presses against the user’s face. In use, flanges 1306 of the elastic seal 1300 are configured to stop the inner tubular member 1301 from rolling up and lifting off the user’s face. Furthermore, the flanges 1306 are also configured to mitigate the longitudinal retraction of the inner tubular member 1301 when the inner tubular member 1301 is stretched circumferentially e.g. in the deployed state during application of the elastic seal 1300 on the face of a user of the face mask assembly 1200. The outer tubular member 1303 of the elastic seal has a first outer tubular member surface 1308 and a second outer tubular member surface 1309. The first outer tubular member surface 1308 is an inward-facing surface 1308. By inward facing, it will be understood that is surface 1308 is contactable with air being breathed in and out of the face mask assembly 1200 during usage of the face mask assembly 1200. The outer tubular member 1303 of the elastic seal is partially collapsible. By partially collapsible, it will be understood that the outer tubular member 1303 may be collapsed in the direction of the mask base 1304 (i.e. in the longitudinal direction of the elastic seal 1300), from the non-collapsed state shown in Figure 48. The collapsibility of the outer tubular member 1303 may be adjustable, for example, by increasing the tension in each strap 1203a, 1203b of the harness 1201. The second tubular member surface 1309 is an outward-facing surface 1309. The outer tubular member may be partially collapsible, in use, to create folds in the inward facing surface 1308. Beneficially, the folds increase the surface area of the inward facing surface 1308 of the outer tubular member 1303 so as to increase the condensation of moisture on this surface 1308. In CPAP applications, users of the CPAP face masks may suffer discomfort from dry mouth and dry nose. In this embodiment, the increased condensation arising as a result of the folds humidifies the air breathed in by a user of the face mask assembly 1200, thereby mitigating or obviating such issues. Yet further advantageously, the folds formable by the partially collapsible outer tubular member 1303 improves the resistance of the inner tubular member 1301 to expansion under pressure, such as when the CPAP face mask assembly 1200 is connected to a CPAP machine. This improves the airtightness of the face mask assembly 1200 around the user’s nose and mouth, even under high pressure conditions e.g. during CPAP therapy. The outer tubular member 1303 being a partially collapsible outer tubular member 1303 also enables the outer tubular member 1303 to reduce the pressure exerted on the face of a wearer of the face mask assembly 1200. In more detail, the compression force exerted on the elastic seal 1300 is partially absorbed by a partially collapsible outer tubular member 1303, which improves the comfort of users wearing the face mask assembly 1200 by reducing the pressure exerted on the face of the wearer of the face mask assembly 1200 via the inner tubular member 1301. In the non-limiting example shown, the outer tubular member 1303 comprises one or more outer tubular members splines 1310. The outer tubular member splines 1310 are functionable as a control means 1310 for adjusting the collapsibility of the outer tubular member 1303. The one or more outer tubular member splines may be homogenously formed as part of the outer tubular member 1310 during the manufacture of the elastic seal 1300. The collapsibility of the outer tubular member 1310 may be adjusted by varying the number of splines and / or stiffness of the splines 1310 incorporated into the outer tubular member 1303. In more detail, if the number of splines and / or stiffness of the splines are increased, this will increase the resilience of the outer tubular member 1310 and thus the collapsibility of the outer tubular member 1310, and vice- versa. The elastic seal 1300 comprises a padding means 1311. The padding means 1311, as best shown in Figure 49, is located on the inner tubular member 1301.The padding means 1311 is formed as part of the inner tubular member 1301. The padding means 1311 comprises a first padding section 1312. The first padding section 1312 may be configured, in use, to plug the concavities formed between the convexities in the nose-mouth contour i.e. on either side of the nose bridge. The first padding section 1312 has a first major pad 1313 and a second major pad 1314. When the elastic seal 1300 is deployed on the face of a wearer of the face mask assembly 1200, i.e. the elastic seal being in the deployed configuration, the first major pad 1312 may be configured to plug a corresponding first concavity of the nose-mouth contour. In the inverted configuration, the second major pad 1313 may be configured to plug a corresponding second concavity of the nose-mouth contour. By plug, we mean that, in use, the pads 1312, 1313 will protrude into the corresponding concavity and seal the gap formed by these concavities e.g. the concavities located in the nose-mouth contour. The padding means 1311 comprises a second padding section 1315. The second padding section 1315 is an undulated padding section 1315 that is configurable, in use, to plug facial hair between the undulations of the undulated padding section 1315. The second padding section 1315 comprises a plurality of undulations. In use, in the embodiment shown where the inner tubular member 1301 of the elastic seal 1300 comprises flanges 1306, the padding means 1311 is configured, in use, to distribute the circumferential stress more evenly around the inner tubular member 1301 to avoid abrupt transition in stress adjacent to the flanges 1305. This reduces the risk of any tear arising from the circumferential stress associated with employment of the elastic seal 1300 in the inverted configuration. Yet further beneficially, the padding means 1311 may be configured to mitigate longitudinal retraction occurring during circumferential stretching of the inner tubular member 1311 in use. This counteracts Poisson deformation during employment of the elastic seal 1300, thereby enabling the elastic seal 1300 to form a tighter seal around the nose-mouth contour of the user of the face mask assembly 1200. In the non-limiting example of the embodiment shown, the elastic seal 1300 comprises a skirting portion 1316. The skirting portion 1316 is locatable on the perimeter 1317 that is functionable, in use, to be the sealing perimeter 1317 around the face of a user of the face mask assembly 1200, as best shown in Figure 48. In use, the skirting portion 1316 is configured to stop the inner tubular member 1301 retracting longitudinally when circumferentially stretched in the inverted configuration, thereby mitigating the Poisson effect associated with the stretching of such an elastic seal 1300. Yet further beneficially, the skirting portion 1316, in use, is operable to seal around the nose-mouth contour and to plug gaps formed between and within pads forming part of the first padding section 1312 and the second padding section 1313. Yet even further beneficially, the skirting portion 1316 is configured to protect the sealing perimeter 1317 from tearing in use. In more detail, when the elastic seal 1300 is in the rest configuration as best shown in Figure 47, the inner tubular member 1301 is in a low energy state. In the rest configuration the skirting portion 1316 is in a high energy state. Where the elastic seal 1300, in the rest configuration, comprises an inner tubular member 1301 in a low energy state and a skirting portion 1316 in a high energy state, the rest configuration is a stable configuration and may be referred to as a first stable state configuration. When the elastic seal is in the deployed configuration, the inner tubular member 1301 is in a high energy state. In the inverted configuration, the skirting portion 1316 is in a low energy state. Where the elastic seal 1300, in the deployed configuration, comprises an inner tubular member 1301 in a low energy state and a skirting portion 1316 in a high energy state, the deployed configuration is a stable configuration and may be referred to as a second stable state configuration. In use, the deployed configuration being a second stable configuration enables the user of the face mask assembly 1200 to easily put on the face mask assembly 1200. In absence of a skirting portion 1316 in the deployed configuration, the inner tubular member 1301 has a tendency to revert to the low energy configuration in the form of the rest configuration, making it more difficult to apply the elastic seal 1300 to an object. Now generally referring to Figures 51 to 62, there is shown another non-limiting example of a face mask assembly 1500 and parts thereof, such as an elastic seal 1600 and a mask body 1700. In Figures 51 and 52, there is shown the face mask assembly 1500. The face mask assembly 1500, in accordance with the other non-limiting examples previously described, comprises an elastic seal 1600 and a mask body 1700. In this example, however, the elastic seal 1600 comprises a first tubular member 1601, a bridging portion 1602 and a second tubular member 1603, wherein the elastic seal is prefabricated such that it has a single stable state configuration, wherein the single stable state configuration is a donning configuration. In contrast to the previous examples of elastic seals, the elastic seal 1600 is prefabricated such that it is unable to be inverted from the donning configuration, in which the elastic seal can be readily applied to the face of a wearer of the face mask assembly, to a nested configuration in which the first tubular member 1601 is nested within the second tubular member 1603 and unavailable for donning on the face of a user. In use, this ensures that the elastic seal is easily and readily donnable by a user of the face mask assembly. This can be achieved, for example, by shortening the length of the second tubular member 1603 relative to the length of the first tubular member 1601 such that the first tubular member 1601 is unable to invert from the deployed configuration to the rest configuration. Furthermore, the elastic seal 1600 has a mask base 1604. The mask base 1604 may also be referred to as an elastic seal base 1604. The elastic seal base 1604 is distal to a first end of the elastic seal 1600, said first end being the end that is arranged to form a seal around the face of a wearer of the face mask assembly 1500. In the non-limiting example shown, the face mask assembly 1500 may be useable as a CPAP face mask assembly 1500. Additionally, the face mask assembly 1500 may be equally applied and advantageous in other ventilation applications, including other non-invasive ventilation applications such as Bilevel Positive Airway Pressure (BiPAP) and minimally invasive ventilation applications which may use oropharyngeal or nasopharyngeal airways for mechanical ventilation of the lungs. The mask body 1700 is integrated into the elastic seal 1600, as will later be described. The elastic seal 1600 is formed from silicone in this non-limiting example, but may be fabricated from other elastic materials e.g. natural rubber, synthetic rubber. The elastic seal 1600, in forming the sealing perimeter 1617, also may seal around the chin of a user and the elastic seal 1600 therefore has an integrated chinstrap function built therein. As described for previous examples, the face mask assembly 1500 and in particular, the elastic seal 1600 is readily cleanable and may be washed using any suitable washing fluid such as a fluid having water and / or soap and / or alcohol to remove any electrostatically attracted matter and / or to sterilise the elastic seal 1600. As the mask body 1700 is integrated in the elastic seal 1600 in this example, there is no risk of alcoholic or organic-solvent based cleaning agents causing the detachment of these two components. The elastic seal 1600 is collapsible in height under compression as best shown in Figures 51 to 54. It will be understood here that height here refers to the distance between the opening 1618 defined between the sealing perimeter 1617 of the first tubular member 1601 and the mask base 1604. For example, where a harness, such as harness 1201, is used for a face mask assembly 1500 comprising the elastic seal 1600 in a compressive securement arrangement, the elastic seal 1600 when donned on the face of a user of the face mask assembly via the first tubular member can be collapsed to a compressed state. Accordingly, the elastic seal 1600 is collapsible from a rest state as shown in Figures 51 to 52 (or uncompressed state) to a compressed state, as best shown in Figures 53 to 54. The elastic seal 1600 is collapsible from a rest state to a compressed state via usage of a harness (not shown). In the rest state, the height of the elastic seal 1600 is greater than when the elastic seal 1600 is in the compressed state. As shown in Figures 53 and 54 here, when the elastic seal 1600 is in the compressed state, the first tubular member 1601 is packed within and / or at least partially encapsulated by the second tubular member 1603 under compression. In the non-limiting example shown, the first tubular member 1601 is packed within and / or at least partially encapsulated by the second tubular member 1603, typically through usage of harness, such as a harness 1201, to compressively secure the face mask assembly 1500 to the face of a wearer. It will therefore be understood here that the first tubular member 1601 of the elastic seal 1600 when donned on the face of wearer via the first tubular member, is packable within and / or at least partially encapsulatable by the second tubular member 1603 under compression. In this way, the second tubular member 1603 is configured to function as buttress for the first tubular member 1601 when the elastic seal 1600 is in the collapsed state. In use, the first tubular member 1601 being packed within and / or at least partially encapsulated by the second tubular member 1603 mitigates expansion of the first tubular member resulting from application of the elastic seal 1600 on the face of a user of the face mask assembly 1500, and more preferably resulting from application of the elastic seal 1600 on the face of a user of the face mask assembly 1500 as a CPAP face mask assembly 1500 during CPAP therapy. It will also be understood here that, in the compressed state, the second tubular member 1603 is configured to seal around the first tubular member 1601 under a compressive force. That is, when the elastic seal 1600 is donned on the face of a wearer of the face mask assembly via the first tubular member 1601, the second tubular member 1603 is compressible to seal around the first tubular member 1601. In this way, the second tubular member 1603 being configured to seal around the first tubular member 1601 in the compressed state thereby enables formation of a further (or second) seal around the seal formed between the first tubular member 1601 and the object to which the elastic seal 1600 is being applied (e.g. the wearer of a face mask assembly 1500 comprising the elastic seal 1600). This further seal may also be referred to as the external seal, and the seal formed between the first tubular member 1601 and the object to which the elastic seal 1600 is being applied may be referred to as the internal (or first) seal. In use, the implementation of this external seal helps to buffer against the compressive force exerted on the face of a user of the face mask assembly 1500 through the harness (e.g. when the harness is in a compressive securement arrangement). It will therefore be understood that the second tubular member 1603 of the elastic seal 1600 is compressible to form a buffering region arranged to absorb at least some of the compressive force exerted on the elastic seal 1600 (e.g. through application of a harness in a compressive securement arrangement). As can be observed in Figures 51 to 54 here, the second tubular member 1603 is configured to seal around the first tubular member 1601 under compression via splaying outwards as a result of said compression. The splaying outwards of second tubular member 1603 accommodates the packing and / or partial encapsulation of the first tubular member 1601 therein. Accordingly, the first tubular member 1603 is configured to splay outwards when the elastic seal 1600, when donned on the face of a user of the face mask assembly, is under compression. In this way, additional elastic seal material is packed more tightly in the space between the first tubular member 1601 and the second tubular member 1603 in order to buffer against the compressive force exerted on the face of a user of the face mask assembly 1500 through the harness (e.g. harness 1201). In other arrangements, such as the non-limiting example of the face mask assembly 1200 shown in Figures 45 to 50, the outer tubular member 1303 can be configured to seal around the inner tubular member 1301 under compression by partially collapsing under compression to create folds in an inward facing surface of the outer tubular member 1303. In other words, the inner tubular member 1301 may be configured to be packed within, or at least partially encapsulated by the folds formed in an inward facing surface of the outer tubular member 1303 that has partially collapsed to form the external seal around the inner tubular member 1301. In this way, additional elastic seal material is packed around the inner tubular member 1301 in order to buffer against the compressive force exerted on the face of a user of the face mask assembly through the harness 1201. Accordingly, the folds formed in an inward facing surface of the outer tubular member 1303 is functionable as a spring-like component to partially absorb the compressive force exerted on the face of a wearer of the face mask assembly 1200. In each of the abovementioned arrangements, the elastic seal 1300, 1600 comprises a buffering region for absorbing at least part of the compression force exerted on the elastic seal 1300, 1600 of the face mask assembly 1200, 1500 (e.g. via the harness in a compressive securement arrangement). That is, in arrangements where the outer tubular member 1303 / second tubular member 1603, is configured to seal around the inner tubular member 1301 / first tubular member 1601 under compression, the elastic seal 1300, 1600 comprises a buffering region for absorbing at least part of the compression force exerted on the elastic seal 1300, 1600 of the face mask assembly 1200, 1500. In this way, the face of a user of the face mask assembly 1200, 1500 may experience less pressure during usage of the face mask assembly 1200, 1500 because of the absorption of some of the compressive force exerted by the harness 1201 on the elastic seal 1300, thereby improving the comfort for a user of such a face mask assembly 1200, 1500. The buffering region of the elastic seal 1600 in the non-limiting example shown in Figures 51 to 54 comprises the bridging portion 1602 and / or at least part of the first tubular member 1619 of the elastic seal 1600. The at least part of the first tubular member 1619 of the buffering region comprises the concave bent portion 1619 forming part of the first tubular member 1601. Now referring to Figure 55, there is shown the mask body 1700 integrated into the elastic seal 1600. As per the non-limiting example of the face mask assembly 1500 as best shown in Figure 46, the mask body 1700 comprises a mask frame 1701. The mask frame 1701 is integrated into the elastic seal 1600. In contrast to the single ring-shaped portion shown in the non-limiting example of Figure 46, the mask frame 1701 as shown in Figure 55 has two ring-shaped portions 1704a, 1704b. Each ring-shaped portion 1704a, 1704b shown in Figure 55 is a circular ring- shaped portion 1704a, 1704b, however, other non-circular arrangements are possible (e.g. polygonal). Each ring-shaped portion 1704a, 1704b defines a respective mask frame aperture therein 1705a, 1705b. In the non-limiting example of Figure 55 one of the ring-shaped portions 1704a is arranged, in use, to support the securement of a connecting means, such as a vent ring, for connecting the face mask assembly 1500 to a CPAP machine. Accordingly, this ring-shaped portion 1704a defines a mask frame aperture 1705a arranged, in use, to support the securement, within the mask base aperture 1705a, of a connecting means for connecting the face mask assembly 1500 to a CPAP machine. In the non-limiting example shown, the two ring-shaped portions 1705a, 1705b comprise a first ring-shaped portion 1705a and a second ring portion 1705b bridged to the first ring-shaped portion 1705a via one or more bridging members 1706. The second ring-shaped portion 1705b defines a second mask frame aperture 1703b, and the first ring-shaped portion 1705a defines a first mask frame aperture 1703a. As shown in Figure 55, the first ring-shaped portion 1705a and the second ring-shaped portion 1705b are concentrically arranged with respect to each other. In the arrangement shown, the first ring-shaped portion 1705a is an innermost ring-shaped portion 1705a, and the second ring-shaped portion 1705b is an outermost ring-shaped portion 1705b. Alternatively, the second ring-shaped portion 1705b can be an outer ring-shaped portion, such as, for example, an intermediate ring portion disposed between the innermost ring-shaped portion and one or more ring-shaped portions. In other words, the mask frame 1701 can include more than two ring-shaped portions, such as three, four, five or more ring-shaped portions. The innermost ring portion 1705a in Figure 55 is the ring-shaped portion 1705a that is arranged in use to support the securement, within the mask base aperture 1605, of a connecting means (e.g. a vent ring) for connecting the face mask assembly 1500 to a CPAP machine. In use, the inclusion of a first ring-shaped portion 1705a and a second ring-shaped portion 1705b bridged to the said first-ring shaped portion 1705a improves the structural strength and prevents blow-out of the mask base 1604 during usage of the face mask assembly 1500 when the face mask assembly is subjected to high pressure conditions, such as when the face mask assembly 1500 is used during CPAP therapy. As shown in Figure 55, the mask body 1700 comprises one or more attachment means 1704 (four shown) extending from the mask frame 1701 in the form of attachment loops 1704. It will therefore be understood here that the mask body 1700 comprises one or more attachment means for attachment of a harness directly and / or indirectly thereto. The attachment loops 1704 as shown in Figure 55 are similar to the attachment loops 1404 as described for the mask body 1400 of the face mask assembly 1200 previously described, with the difference being that the attachment loops 1704 extend from the outermost ring-shaped portion 1704b of the mask frame 1701 in Figure 55, rather than the single ring-shaped portion of the mask frame 1401. Each attachment loop 1704 extends through the elastic seal 1600, and, in particular, extends through a corresponding slit formed within the mask base 1604 for protrusion of the attachment means 1704 therethrough. In other embodiments, however, the mask body 1700 can be separate from and securable within and / or to the elastic seal 1600. In these embodiments, the mask body 1700 may be arranged to directly secure the connecting means for connecting a CPAP machine to the facemask assembly. It will also be understood that other attachment mechanisms are possible; for example, the elastic seal 1600 may comprise attachment means integrated into the elastic seal 1600 for coupling of a harness directly and / or directly thereto. Each attachment loop 1704 as shown in Figure 55 is configured for a harness, such as the harness 1201 as previously shown and described in Figures 38 to 44, to be coupled directly and / or indirectly thereto. In use, in examples wherein the, or each, strap 1203a, 1203b of the harness 1201 is coupled directly and / or indirectly to one or more attachment loops 1704, each loop 1704 is rotatable, in use, about a first orthogonal axis, said first orthogonal axis being the longitudinal axis of the attachment loop 1704, a second orthogonal axis, and a third orthogonal axis, wherein rotation about the first orthogonal axis provides each strap 1203a, 1203b directly and / or indirectly coupled to a respective attachment loop 1704 with an additional torsional component to the tangential pull exerted by the, or each, strap 1203a, 1203b. This enables the face mask assembly 1500 to accommodate different head pull directions associated with user’s having different head shapes and sizes. Furthermore, as shown in Figure 55, the face mask assembly 1500 has one or more intermediary coupling members 1502 (four shown) for indirectly coupling the harness to the elastic seal 1600 and / or mask body 1700. The harness (not shown) can be indirectly coupled to one or more attachment means 1704 of the mask body via the one or more intermediary coupling members 1502. The one or more intermediary coupling members 1502 in this example are one or more coupling loops 1502. The one or more coupling loops 1502 are configured to enable angular adjustment of the harness in use. In particular, in embodiments wherein each strap comprises a securing means that is operable, in use, to form a securing loop, such as the securing loop 1207 that is described for the harness 1201, the securing loop can be secured to a respective coupling loop 1502 and is slidable about the respective loop 1502. In use, this provides the face mask assembly 1500 with the ability to accommodate different three-dimensional shapes associated with users of the face mask assembly 1500. Now generally referring to Figures 56 to 59, there is shown the face mask assembly 1500 and the padding means 1611 thereof. The elastic seal 1600 comprises a padding means 1611. The padding means 1611 is located on the first tubular member 1601.The padding means 1611 is formed as part of the first tubular member 1601. The padding means 1611 extends along at least part of the length of the first tubular member 1601. In the non-limiting example shown, the padding means 1611 has a nose pad 1620. The nose pad 1620 is homogenously formed as part of the elastic seal 1600, and more particularly, the first tubular member 1601. The nose pad 1620 comprises a first nose pad portion 1620a and a second nose pad portion 1620b. The nose pad is dimensioned such that an arch-shaped recess 1621 is defined by at least part of the first nose pad portion 1622a and at least part of the second nose pad portion 1622b. The nose pad 1620 is configured to have a pre-formed shape. The nose pad 1620 is configured to, in use, to plug the concavities formed between the convexities on either side of the nose bridge. The nose pad 1620 is adapted to seal around the nose bridge of the wearer of the face mask assembly 1500. As best shown in Figures 57 and 58, the nose pad 1620 is configured, in use, to seal around the nose bridge of the wearer such that curvature over the nose bridge is reduced. In Figure 57, there is shown an exploded cross-sectional view including a slanted coronal section of the nose-mouth contour of a wearer of the face mask assembly, as well as the nose pad 1620. As shown in Figure 57, the nose-mouth contour around the nose bridge of a wearer of the face mask assembly has a mixed convex-concave contour. In Figure 58, there is shown the nose pad 1620 sealed around the nose of the wearer of the face mask assembly. The nose pad is configured, in use, to seal around the nose of the wearer such that a generally convex sealing perimeter is obtained around the nose and mouth of the wearer. In other words, the nose pad 1620 is operable to modify the contour of the nose bridge from being a mixed convex-concave contour, as shown in Figure 57, into a substantially convex contour, as shown in Figure 58. In use, the nose pad 1620 is configured to reduce and redirect the normal pressure for a given tangential tension around the facial contour being sealed around. As best shown in Figure 59, the nose pad 1620 is configured, in use, to extend along at least part of the nose bridge to distribute the normal force exerted on the nose and cheeks of a user of the face mask assembly 1500. In use, this distribution of normal force reduces the pressure exerted on the user of a face mask assembly 1500, thereby improving the comfort for the user. The nose pad 1620 is configured to extend in the direction orthogonal to the plane containing the tension. Furthermore, the nose pad 1620 is configured, in use, to rest on the alae of the nose of a user of the face mask assembly 1500. That is, each nose pad portion 1620a, 1620b may comprise a resting portion 1627a, 1627b that is arrangeable, in use, to rest on a respective ala of the nose of a wearer of the face mask assembly 1500. In use, the resting of the nose pad 1620 on the alae of the nose aids in stabilising the position of the face mask assembly 1500 on the face of a wearer of said assembly 1500. In the non-limiting example shown, the padding means 1611 has a padding section 1623 that is functionable as a reinforcement padding section 1623 for reinforcing the first tubular member 1601. The padding section 1623 may therefore be referred to as the reinforcement padding section 1623. The reinforcement padding section 1623 is configured to stabilise the first tubular member 1601 in the donning configuration. The reinforcement padding section 1623 is configured to prevent the retraction of the elastic seal 1600 on the face of a wearer of the face mask assembly 1500. The reinforcement padding section 1600 is configured to prevent the pressing down of the elastic seal 1600 on the face of a wearer of the face mask assembly 1500. The reinforcement padding section 1611 is arranged to distribute the compressive stress associated with the first tubular member 1601 being prefabricated to be in the donning configuration. The reinforcement padding section 1623 extends from the skirting portion 1616 of the first tubular member 1601 to the concave bent portion 1619 of the first tubular member 1601. The reinforcement padding section 1623 is substantially located on the outer surface of the first tubular member 1601.The reinforcement padding section 1623 has an undulated profile. The reinforcement padding section 1623 spans substantially the entirety of the circumference of the first tubular member 1601. The reinforcement padding section 1623 is homogenously formed as part of the first tubular member. The reinforcement padding section 1623 has three pairs of reinforcement pads 1624a, 1624b, 1624c. Each pad of the three pairs of reinforcement pads 1624a, 1624b, 1624c has substantially equal maximal thickness. Each pad of the three pairs of reinforcement pads 1624a, 1624b, 1624c has a wave-like profile. Each pad of the three pairs of reinforcement pads 1624a, 1624b, 1624c has a variable thickness. Each pad of the three pairs of reinforcement pads 1624a, 1624b, 1624c is equispaced angularly about the circumference of the first tubular member 1601. In use, this assists in evenly distributing the compressive stress arising from the prefabrication of the first tubular member 1601 in the donning configuration. This further assists in preventing the retraction of and pressing down of the elastic seal 1600 on the face of a wearer of the face mask assembly and further assists in stabilising the elastic seal 1600 in the donning configuration. As shown in Figure 56, the padding section 1623 extends along part of the length of the first tubular member 1601. In Figure 56, there is shown a section, A, of the first tubular member 1601 in which the padding section 1623 is located. Furthermore, there is shown a section B in which the padding section 1623 is located. It will be understood here that padding section 1623 extends continuously along the length of the first tubular member 1601 from section A to Section B. Furthermore, in section B, there is shown the nose pad 1620 of the first tubular member 1601. As shown in Figure 56, the first tubular member 1601 has a bent portion 1619. The bent portion 1619 is a concave bent portion 1619. The concave bent portion 1619 is adjacent to the bridging portion 1602 of the elastic seal 1600. In prior examples, the concave bent portion was formed via inversion of the inner tubular member to a deployed configuration to form the concave bent portion and to minimise the potential energy stored in the elasticity of the seal. However, in the present example the concave bent portion 1619 may be preformed as part of the first tubular member 1601. That is, the elastic seal is prefabricated such that the first tubular member has a concave bent portion 1619. The first tubular member 1601, and in particular, the bent portion 1619 comprises at least one protrusion 1606. The at least one protrusion 1606 is formable from the first tubular member 1601. The at least one protrusion 1606 is at least one ridge 1606 or at least one flange 1606. The at least one ridge 1606 or at least one flange 1606 may also be referred to at least one spline 1606. In the arrangement as best shown in Figure 56, the at least one protrusion 1606 partially extends along the length of the first tubular member 1601. The at least one protrusion 1606 is arranged to extend from a first end 1626a of the concave bent portion 1619 to a second end 1626b of the concave bent portion 1619. The first end 1626a of the concave bent portion 1619 is located adjacent to the bridging portion 1602. The second end 1626b of the concave bent portion 1619 is located adjacent to the padding means 1611. In other words, the concave bent portion 1619 may comprise the at least one protrusion 1626. In use, in the non-limiting example shown in Figures 51 to 62, where the first tubular member 1601 of the elastic seal 1600 comprises flanges 1606, the padding means 1611 is configured, in use, to distribute the circumferential stress more evenly around the first tubular member 1601 to avoid abrupt transition in stress adjacent to the flanges 1606. This reduces the risk of any tear arising from the circumferential stress associated with employment of the elastic seal 1600 in the donning configuration. Yet further beneficially, the padding means 1611 is configured to mitigate longitudinal retraction occurring during circumferential stretching of the first tubular member 1611 in use. This counteracts Poisson deformation during application of the elastic seal 1600 on the face of a wearer of the face mask assembly, thereby enabling the elastic seal 1600 to form a tighter seal around the nose-mouth contour of the user of the face mask assembly 1500. Furthermore, as best shown in Figure 56, the second tubular member 1603 comprises one or more second tubular member splines 1610. The second tubular member splines 1610 can function in the same manner as the outer tubular member splines 1310 described previously. As best shown in Figure 56, the elastic seal comprises a skirting portion 1616. The skirting portion 1616 is located on the perimeter 1617 that is functionable, in use, to form the sealing perimeter 1617 around the face of a user of the face mask assembly 1500. In use, the skirting portion 1616 is configured to stop the first tubular member 1601 retracting longitudinally when circumferentially stretched in the donning configuration, thereby mitigating the Poisson effect associated with the stretching of such an elastic seal 1600. Yet further beneficially, the skirting portion 1616, in use, is operable to seal around the nose-mouth contour and to plug gaps formed between pads comprised by the padding means 1611. Yet even further beneficially, the skirting portion 1616 is configured to protect the sealing perimeter 1617 from tearing in use. Now referring to Figure 60, there is shown a three-dimensional perspective view of the nose-mouth contour 1800 of a wearer of a face mask assembly 1500, with the nose concavities shown. As shown in Figures 61 and 62, there is shown the face mask assembly 1500 being applied to seal around the nose and mouth of a wearer of the face mask assembly 1500. As shown in Figure 62, the skirting portion 1616 is configured to seal around the nose and mouth of the user of the face mask assembly 1500 in the sagittal plane. Furthermore, the first tubular member 1601 is arranged to seal around the nose and mouth of the user of the face mask assembly 1500 in the coronal plane. The elastic seal 1600 is deformable to seal around the nose- mouth contour of the wearer of the face mask assembly 1500 through radial constriction and longitudinal compression. Various combinations of optional features have been described herein, and it will be appreciated that described features may be combined in any suitable combination. In particular, the features of any one example embodiment may be combined with features of any other embodiment, as appropriate, except where such combinations are mutually exclusive. Throughout this specification, the term “comprising” or “comprises” means including the component(s) specified but not to the exclusion of the presence of others. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features. The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

CLAIMS 1. An elastic seal for a face mask assembly, the elastic seal comprising: a first tubular member that is arranged for forming a sealing perimeter around the face of a wearer, a second tubular member, and a bridging portion; wherein the elastic seal is prefabricated such that it has a single stable state configuration, wherein the single stable state configuration is a donning configuration.

2. An elastic seal as claimed in claim 1, wherein the first tubular member comprises a bent portion.

3. An elastic seal as claimed in claim 2, wherein the bent portion is a concave bent portion.

4. An elastic seal as claimed in claim 2 or claim 3, wherein the bent portion is adjacent to the bridging portion of the elastic seal.

5. An elastic seal as claimed in any one of claims 2 to 4, wherein the bent portion comprises at least one protrusion formed from the first tubular member.

6. An elastic seal as claimed in any preceding claim, wherein the first tubular member has a first tubular member length, and the second tubular member has a second tubular member length, wherein the second tubular member length is shorter than the first tubular member length.

7. An elastic seal as claimed in any preceding claim, wherein the first tubular member of the elastic seal, in an unworn state, is arranged to extend away from, and is not nested within, the second tubular member.

8. An elastic seal as claimed in any preceding claim, wherein the elastic seal comprises an elastic seal base.

9. An elastic seal as claimed in claim 8, wherein the mask base comprises an elastic seal base aperture.

10. An elastic seal as claimed in any preceding claim, wherein the elastic seal comprises a padding means.

11. An elastic seal as claimed in claim 10, wherein the padding means extends along at least part of the length of the first tubular member.

12. An elastic seal as claimed in claim 10 or claim 11, wherein the padding means comprises a padding section that is functionable as a reinforcement padding section for reinforcing the first tubular member.

13. An elastic seal as claimed in claim 12, wherein the reinforcement padding section is configured to stabilise the first tubular member in the donning configuration.

14. An elastic seal as claimed in any one of claims 10 to 13, wherein the padding means comprises a nose pad.

15. An elastic seal as claimed in claim 14, wherein the nose pad is homogeneously formed as part of the first tubular member.

16. An elastic seal as claimed in claim 14 or claim 15, wherein the nose pad comprises a first nose pad portion and a second nose pad portion.

17. An elastic seal as claimed in claim 16, wherein the nose pad is dimensioned such that an arch-shaped recess is defined by at least part of the first nose pad portion and at least part of the second nose pad portion.

18. An elastic seal as claimed in any one of claims 14 to 17, wherein the nose pad is adapted to seal around the nose bridge of the wearer of the face mask assembly.

19. An elastic seal as claimed in any one of claims 14 to 18, wherein the nose pad is configured to reduce and redirect the normal pressure for a given tangential tension around the facial contour.

20. An elastic seal as claimed in any preceding claim, wherein the elastic seal is collapsible from a rest state to a compressed state.

21. An elastic seal as claimed in any preceding claim, wherein the first tubular member of the elastic seal is packable within or at least partially encapsulatable by the second tubular member when the elastic seal is compressed.

22. An elastic seal as claimed in any preceding claim, wherein the second tubular member is configured to seal around the first tubular member under a compressive force.

23. An elastic seal as claimed in claim 22, wherein, when the elastic seal is compressed, the second tubular member is arranged to seal around the first tubular member by splaying outwards as a result of said compression and to accommodate the packing or partial encapsulation of the first tubular member therein.

24. An elastic seal as claimed in any preceding claim, wherein the elastic seal comprises a buffering region for absorbing at least part of the compression force exerted on the elastic seal.

25. An elastic seal as claimed in claim 24, wherein the buffering region comprises the bridging portion and / or at least part of the first tubular member of the elastic seal.

26. An elastic seal as claimed in claim 25, when dependent on claim 3, wherein the at least part of the first tubular member of the buffering region comprises the concave bent portion forming part of the first tubular member.

27. An elastic seal as claimed in any preceding claim, wherein the elastic seal comprises a skirting portion.

28. An elastic seal as claimed in any preceding claim, wherein the elastic seal is formed from silicone.

29. A face mask assembly, the face mask assembly comprising an elastic seal as claimed in any one of claims 1 to 28.

30. A face mask assembly as claimed in claim 29, wherein the face mask assembly comprises a mask body.

31. A face mask assembly as claimed in claim 30, wherein the mask body comprises a mask frame.

32. A face mask assembly as claimed in claim 31 wherein the mask body comprises a mask frame integrated into the elastic seal.

33. A face mask assembly as claimed in claim 32, wherein the mask frame comprises at least one ring-shaped portion.

34. A face mask assembly as claimed in claim 33, wherein the at least one ring-shaped portion comprise a single ring-shaped portion or a plurality of ring-shaped portions.

35. A face mask assembly as claimed in claim 33 or claim 34, wherein the at least one ring- shaped portion includes a ring-shaped portion that is arranged, in use, to support the securement of a connecting means for connecting the face mask assembly to a CPAP machine.

36. A face mask assembly as claimed in any one of claims 33 to 35, wherein the at least one ring-shaped portion comprises a first ring-shaped portion and a second ring portion bridged to the first ring-shaped portion via one or more bridging members.

37. A face mask assembly as claimed in claim 36, wherein the first ring-shaped portion and the second ring-shaped portion are concentrically arranged with respect to each other.

38. A face mask assembly as claimed in one of claims 30 to 37, wherein the mask body comprises one or more attachment means extending from the mask frame, wherein the, or each, attachment means is configured for a harness to be coupled directly and / or indirectly thereto.

39. A face mask assembly as claimed in any one of claims 29 to 38, wherein the face mask assembly comprises a harness arranged to support the elastic seal on the object.

40. A face mask assembly as claimed in any one of claims 29 to 39, wherein the face mask assembly is functionable as a CPAP face mask assembly.

41. A face mask assembly as claimed in claim 40, wherein the elastic seal and / or mask body is connectable to a CPAP machine.

42. A face mask assembly as claimed in claim 30 or claim 31, wherein the mask body comprises a filter means.

43. A face mask assembly as claimed in claim 42, wherein at least part of or all of the mask frame and / or at least part of or all of the filter means is pleated.

44. A continuous positive airway pressure (CPAP) system, the CPAP system comprising: a CPAP machine; and a face mask assembly as claimed in any one of claims 29 to 41.

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