Mouth-nose thermosensitive airflow sensor

Abstract

The utility model discloses a mouth-nose thermosensitive airflow sensor, which comprises a middle shell, the middle shell is connected with a flexible lead, the flexible lead is provided with a detection unit, the middle shell is connected with a transmission unit communicated with the detection unit, and the flexible lead and the middle shell are connected to form an annular structure. The utility model provides a mouth-nose thermosensitive airflow sensor, which can reduce interference when the mouth-nose thermosensitive airflow sensor is matched with a nasal oxygen cannula for use, reduce foreign body sensation in the nose, avoid influence on normal respiration of a patient, reduce contact between the thermosensitive airflow sensor and skin, reduce influence of skin temperature on acquisition precision, and improve acquisition accuracy. And the temperature response of gas exchange can be more sensitive when the nasal cavity is placed outside the nasal cavity.

Description

Technical Field

[0001] The utility model relates to the technical field of medical devices, in particular to an oral and nasal thermal airflow sensor. Background Art

[0002] In clinical medicine, oral and nasal airflow detection is an important auxiliary diagnostic parameter and has great clinical significance. For severe patients, nasal oxygen cannula is generally required for assistance. At the same time, the patient should be as comfortable as possible during the oral and nasal airflow detection to avoid too many interference factors to the patient.

[0003] For example, the publication number "CN215874647U" discloses "a replaceable oral and nasal airflow thermistor", including a sensor component, a shell component, an input connection component, an output connection component and an outer shell wrapping sleeve, wherein the shell component includes a lower shell and an upper shell that are detachably mounted and hollow inside, and the lower shell is provided with an oral positioning hole input wire terminal and an output wire terminal, and the upper shell includes a first upper shell and a second upper shell that are symmetrically arranged opposite to each other, and also includes a pair of first positioning grooves and a pair of second positioning grooves; the interior of the upper shell is filled with a mist adsorption layer; the input connection component is connected to the input wire terminal, and the output connection component is connected to the output wire terminal; the outer shell wrapping sleeve is put on the outside of the shell component, and the oral and nasal airflow thermistor can be fixed on the face by a fixing belt. However, in actual applications, such sensors will interfere with the use of nasal oxygen tubes, and because of the insertion detection method, they will also cause physiological interference to patients. Summary of the invention

[0004] In view of the problems mentioned in the background technology that the prior art has interference with the nasal oxygen cannula and the detection method is uncomfortable, the utility model provides an oral and nasal thermal airflow sensor, which can reduce interference when used in conjunction with the nasal oxygen cannula, while reducing the foreign body sensation in the nose and avoiding affecting the patient's normal breathing. At the same time, it reduces the contact between the thermal airflow sensor and the skin, reduces the influence of skin temperature on the collection accuracy, and is placed outside the nasal cavity to be more sensitive to the temperature of gas exchange.

[0005] To achieve the above purpose, the utility model adopts the following technical solutions.

[0006] A mouth and nose thermal airflow sensor comprises an intermediate shell, the intermediate shell is connected with a soft lead, a detection unit is arranged on the soft lead, a transmission unit connected with the detection unit is connected to the intermediate shell, and the soft lead is connected with the intermediate shell to form a ring structure. In the prior art, the thermal airflow sensor of the mouth and nose is generally set in a columnar shape, so it is necessary to go deep into the nasal cavity for detection. At the same time, since the sensor in the prior art needs to go deep into the nasal cavity, it conflicts with the use of the nasal oxygen tube, that is, the two can only control one task at the same time. When the patient needs to use the nasal oxygen tube, if the nasal oxygen tube is removed for detection, the patient cannot be assisted to breathe, which will also cause inaccuracy of the actual data. If the two cannot work at the same time, it is also necessary to consider whether the patient will have difficulty breathing due to the loss of the assistance of the nasal oxygen tube during the sensor detection process. Going deep into the nasal cavity will cause the nasal mucosa and the thermal sensor to contact, causing the skin temperature to heat up the thermal sensor, reducing the collection sensitivity and accuracy; in the present application, the soft lead is set into a ring structure, thereby leaving a gap, so that the nasal oxygen tube can pass through the ring structure during use, the soft lead is sleeved on the nasal oxygen tube and is located on the outside of the nasal cavity, and the exhaled airflow of the nasal cavity is detected by the detection unit for numerical recording. At the same time, the nasal oxygen tube can continuously assist the patient in breathing. At the same time, in the present application, when the nasal oxygen tube is not needed, it can also be used separately. The detection is performed while reducing the probability of contact with the skin and improving the measurement accuracy. The soft lead can be adaptively bent and deformed. Further, the deformation of the soft lead is preferably plastic deformation, so as to ensure that the annular structure formed by the soft lead has strong plasticity and can adapt to nasal oxygen tubes of different sizes and different patients. After bending and adjustment, the detection unit on the soft lead can be more adapted to the patient's air outlet direction, thereby ensuring the detection accuracy. The transmission unit connected to the intermediate shell can transmit the collected signal on the detection unit, wherein the transmission unit can be an extension of the soft lead, which is integrally formed with the soft lead, and the transmission wire is built into the soft lead. The transmission unit is connected to the detection unit, which also means that the soft lead is connected to the detection unit and directly outputs as the transmission unit. Similarly, the transmission unit can also be connected to the detection unit separately; the soft lead is connected to the intermediate shell to form an annular structure. On the one hand, when used in conjunction with the nasal oxygen tube, it can limit the nasal oxygen tube to avoid separation, and at the same time can reduce the obstruction to the exhaled airflow, and at the same time can reduce the probability of contact with the skin, ensure the accuracy of the detection, and avoid interference with the patient.

[0007] Preferably, the soft lead includes a nose detection part and a mouth detection part, and the nose detection part and the mouth detection part are respectively arranged on both sides of the intermediate housing. The soft lead is connected to the intermediate housing to form a nose detection part and a mouth detection part respectively, so as to detect the nasal exhalation and the mouth exhalation respectively, wherein the nose detection part and the mouth detection part are respectively located on both sides of the intermediate housing, and the intermediate housing is placed in the middle to play a fixing role, and the nose detection part and the mouth detection part located on both sides can synchronously detect the airflow.

[0008] Preferably, the soft lead is bent through the intermediate housing to form a nose detection part and a mouth detection part, and the nose detection part and the mouth detection part are integrally formed. The soft lead on the nose detection part and the soft lead on the mouth detection part are integrally formed, and are formed by the same soft lead passing through the intermediate housing and bending.

[0009] Preferably, the intermediate shell includes a fitting cambered surface. The intermediate shell is provided with a fitting cambered surface, which can ensure a fitting effect with the patient, making it more comfortable and ergonomic.

[0010] Preferably, the soft lead includes a nose detection part, which is provided with two nose-side annular hoses, each of which is provided with a detection unit. The nose detection part is composed of two nose-side annular hoses, which correspond to the two nasal cavities and can be adapted to the nasal oxygen tube. The two nose-side annular hoses are provided with a detection unit, thereby improving the accuracy of the detection.

[0011] Preferably, a connection hole is formed between the nose-side annular hose and the intermediate shell, and the connection hole can be detachably connected to the nasal oxygen tube. A connection hole is formed in the middle of the nose-side annular hose, and the connection hole can be detachably connected to the nasal oxygen tube. At the same time, due to the plastic deformation characteristics of the soft lead, it can be bent upward, and the entire sensor forms an "L"-shaped structure, thereby ensuring that the nose detection part and the nasal oxygen tube can work at the same time.

[0012] Preferably, the nose-side annular hose includes a proximal middle portion, and the detection unit is arranged on the proximal middle portion. The nose-side annular hose includes a proximal middle portion, wherein the proximal middle portion is a soft lead arranged near the middle position, and the detection unit is arranged on the proximal middle portion, so that the distance between the two detection units can be quickly adjusted when dealing with different patients, thereby ensuring the accuracy of the detection.

[0013] Preferably, the soft lead includes an outlet detection part, the outlet detection part includes an outlet side long hose, and the outlet side long hose is provided with a detection unit on the side away from the intermediate shell. The outlet detection part formed by the soft lead is provided with an outlet side long hose, wherein the outlet side long hose is provided with a longer size, so as to adapt to position adjustment under different states, and ensure that the detection unit on the outlet side long hose can be closer to the airflow position.

[0014] Preferably, the transmission unit is arranged at the end of the intermediate housing, and the arrangement direction of the transmission unit is staggered with the arrangement direction of the soft lead. The transmission unit is arranged at the end of the intermediate housing, so that the arrangement of the transmission unit can avoid interfering with the soft lead.

[0015] Preferably, the intermediate housing is a color-changing housing; or / and the soft lead is a color-changing lead. In this application, the intermediate housing and the soft lead can be made of color-changing materials, which can change color in the case of aging after being used for a long time, thereby reminding the user.

[0016] Preferably, the soft lead extends along both ends of the intermediate housing to form a transmission unit. The transmission unit is an extension of the soft lead, thereby ensuring the stability of signal transmission, reducing assembly and connection steps, and improving production efficiency.

[0017] The structural design of the present application can reduce contact with the skin and reduce the contact between the deep nasal mucosa and the thermistor, which causes the skin temperature to affect the thermistor, causing temperature rise and reducing the collection sensitivity and accuracy.

[0018] The beneficial effects of the utility model are as follows:

[0019] (1) It can detect airflow in the mouth and nose at the same time, which improves the adaptability of the device to different nasal oxygen tubes and different patients;

[0020] (2) It can be used simultaneously with the nasal oxygen cannula without interference and avoids deep nose detection, thus reducing the foreign body sensation;

[0021] (3) More comfortable to use, the middle shell is more ergonomic;

[0022] (4) Compatible with nasal oxygen cannulas of different sizes;

[0023] (5) Reduce the impact of skin contact on thermal sensors. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is the first axonometric drawing of the utility model.

[0025] Figure 2 It is a top view of the utility model.

[0026] Figure 3 It is a side view of the utility model.

[0027] Figure 4 It is the second axonometric drawing of the present utility model.

[0028] Figure 5 It is a local axonometric drawing of the utility model.

[0029] Figure 6It is the third axonometric drawing of the present utility model.

[0030] In the figure:

[0031] 1 intermediate shell, 11 fits the curved surface;

[0032] 2 soft lead, 21 nose detection part, 22 mouth detection part, 23 nose side annular hose, 24 connection hole, 25 proximal part, 26 mouth side long hose;

[0033] 3. Detection unit;

[0034] 4 transmission unit;

[0035] 5. Nasal oxygen cannula. DETAILED DESCRIPTION

[0036] The utility model is further described below in conjunction with the accompanying drawings and specific embodiments.

[0037] Embodiment 1:

[0038] like Figure 1 , 2 As shown in , 5, a mouth-nose thermal airflow sensor includes an intermediate shell 1, the intermediate shell 1 is connected to a soft lead 2, a detection unit 3 is arranged on the soft lead 2, the intermediate shell 1 is connected to a transmission unit 4 connected to the detection unit 3, the soft lead 2 and the intermediate shell 1 are connected to form a ring structure, the soft lead 2 includes a nose detection part 21 and a mouth detection part 22, the nose detection part 21 and the mouth detection part 22 are respectively arranged on both sides of the intermediate shell 1, the soft lead 2 is bent and passes through the intermediate shell 1 to form the nose detection part 21 and the mouth detection part 22, and the nose detection part 21 and the mouth detection part 22 are integrally formed.

[0039] In the prior art, the thermal airflow sensor of the mouth and nose is generally arranged in a columnar shape, so that it is necessary to go deep into the nasal cavity for detection. At the same time, since the sensor in the prior art needs to go deep into the nasal cavity, it conflicts with the use of the nasal oxygen tube 5, that is, the two can only control one work at the same time. When the patient needs to use the nasal oxygen tube 5, if the nasal oxygen tube 5 is removed for detection, it cannot assist the patient to breathe, which will also cause inaccurate actual data. If the two cannot work at the same time, it is also necessary to consider whether the use of the sensor detection process will cause the patient to lose the assistance of the nasal oxygen tube 5 and cause breathing problems. In difficult situations, penetrating deep into the nasal cavity will cause the nasal mucosa to contact with the thermal sensor, causing the skin temperature to heat up the thermal sensor, reducing the collection sensitivity and accuracy; in the present application, the soft lead 2 is set into a ring structure, thereby leaving a gap so that the nasal oxygen tube 5 can pass through the ring structure during use, and the soft lead 2 is sleeved on the nasal oxygen tube 5 and is located on the outside of the nasal cavity. The exhaled airflow of the nasal cavity is detected by the detection unit 3 for numerical recording. At the same time, the nasal oxygen tube 5 can continuously assist the patient in breathing. At the same time, in the present application, when the nasal oxygen tube 5 is not needed, it can also be detected separately. The probability of contact with the skin is reduced, and the measurement accuracy is improved. The soft lead 2 can be bent and deformed adaptively. Further, the deformation of the soft lead 2 is preferably plastic deformation, so that the annular structure formed by the soft lead 2 has strong plasticity and can adapt to nasal oxygen tubes 5 of different sizes. Similarly, it can adapt to different patients. After bending and adjustment, the detection unit 3 on the soft lead 2 can be more adapted to the patient's air outlet direction, thereby ensuring the detection accuracy. The transmission unit 4 connected to the intermediate shell 1 can transmit the collected signal on the detection unit 3, wherein the transmission unit 4 can be the soft lead 2 The extended part is integrally formed with the soft lead, and the transmission wire is built into the soft lead 2. The transmission unit 4 is connected to the detection unit 3, which also means that the soft lead 2 is connected to the detection unit 3 and directly serves as the output of the transmission unit 4. Similarly, the transmission unit 4 can also be connected to the detection unit 3 separately; the soft lead 2 is connected to the intermediate shell 1 to form a ring structure. On the one hand, when used in conjunction with the nasal oxygen tube 5, it can limit the nasal oxygen tube 5 to avoid separation, and at the same time reduce the obstruction to the exhaled airflow, and at the same time reduce the probability of contact with the skin, thereby ensuring the accuracy of the detection and avoiding interference to the patient.

[0040] The soft lead 2 is connected to the intermediate shell 1 to form a nose detection part 21 and a mouth detection part 22 respectively, so as to detect nasal breathing and oral breathing respectively, wherein the nose detection part 21 and the mouth detection part 22 are respectively located on both sides of the intermediate shell 1, and the intermediate shell 1 is placed in the middle to play a fixing role, and the nose detection part 21 and the mouth detection part 22 located on both sides can synchronously detect the airflow.

[0041] The soft lead 2 on the nose detection part 21 and the soft lead 2 on the mouth detection part 22 are integrally formed, and the same soft lead 2 passes through the intermediate housing 1 and is bent and formed.

[0042] like Figure 3 As shown, the intermediate shell 1 includes a fitting arc surface 11. The intermediate shell 1 is provided with the fitting arc surface 11, which can ensure the fitting effect between the intermediate shell 1 and the patient, making it more comfortable and ergonomic.

[0043] like Figure 1 , 2 As shown in , 4 , the soft lead 2 includes a nose detection part 21 , and the nose detection part 21 is provided with two nose side annular hoses 23 , and each nose side annular hose 23 is provided with a detection unit 3 , and the nose side annular hose 23 includes a proximal part 25 , and the detection unit 3 is arranged on the proximal part 25 .

[0044] The nasal detection part 21 is composed of two nasal annular hoses 23, which correspond to the two nasal cavities and can be adapted to the nasal oxygen tube 5. The two nasal annular hoses 23 are both provided with detection units 3, so as to improve the accuracy of detection. The nasal annular hoses 23 include a proximal part 25, wherein the proximal part 25 is a soft lead 2 arranged close to the middle position. The detection unit 3 is arranged on the proximal part 25, so that the distance between the two detection units 3 can be quickly adjusted when dealing with different patients, thereby ensuring the accuracy of detection.

[0045] like Figure 1 , 2 As shown in Figures 4 and 5, the flexible lead 2 includes an orifice detection portion 22, and the orifice detection portion 22 includes an orifice side long hose 26, and a detection unit 3 is arranged on the side of the orifice side long hose 26 away from the intermediate housing 1. The orifice detection portion 22 formed by the flexible lead 2 is provided with an orifice side long hose 26, wherein the orifice side long hose 26 is arranged with a relatively long size, so that it can adapt to position adjustment under different states, and ensure that the detection unit 3 on the orifice side long hose 26 can be closer to the airflow position.

[0046] like Figure 1 , 5 As shown, the transmission unit 4 is arranged at the end of the intermediate housing 1 , and the arrangement direction of the transmission unit 4 is staggered with the arrangement direction of the soft lead 2 , and the soft lead 2 extends along both ends of the intermediate housing 1 to form the transmission unit 4 .

[0047] The transmission unit 4 is arranged at the end of the intermediate housing 1, so as to avoid the setting of the transmission unit 4 interfering with the soft lead 2. The transmission unit 4 is an extension of the soft lead 2, so as to ensure the stability of signal transmission, reduce assembly connection steps, and improve production efficiency.

[0048] The intermediate housing 1 is a color-changing housing; or / and the soft lead 2 is a color-changing lead. In this application, the intermediate housing 1 and the soft lead 2 can be made of color-changing materials, which can change color in the case of aging after being used for a long time, thereby reminding the user.

[0049] The assembly and working process of the oral and nasal thermal airflow sensor in this embodiment are as follows: in this embodiment, the sensor is in an initial state, and an intermediate shell 1 is provided in this embodiment, and a soft lead 2 is provided on the intermediate shell 1, wherein the soft lead 2 in this embodiment is a continuous line, which passes through the intermediate shell 1 in sequence after repeated bending, and forms a nose detection part 21 and a mouth detection part 22, wherein in this embodiment, the nose detection part 21 includes two nose side annular hoses 23, and a connecting hole 24 is formed between the nose side annular hose 23 and the intermediate shell 1, wherein the soft lead 2 in this embodiment can be bent and deformed, so as to change the shape, position, orientation, etc. of the nose detection part 21 in all directions, and in this embodiment, the nose detection part 21 is provided with two nose side annular hoses 23, each nose side annular hose 23 is provided with a proximal portion 25 in position, which means the position where the two nose side annular hoses 23 are close to each other, and a detection unit 3 is provided on the proximal portion 25, and the detection unit 3 in this embodiment It is a thermistor, and the thermistor is arranged near the middle part of the near-middle part 25, and is not arranged at the end, so as to avoid interference when the nose-side annular hose 23 is bent. There are two nose-side annular hoses 23, and the oral-side long hose 26 on the other side is connected to the two nose-side annular hoses 23 at the same time, so the oral-side long hose 26 is arranged between the two nose-side annular hoses 23. There is only one oral-side long hose 26, and the oral-side field hose passes through the intermediate shell 1 to be connected with the nose-side annular hose 23. A detection unit 3 is arranged on the side of the oral-side long hose 26 away from the intermediate shell 1. The detection unit 3 here is also a thermistor. Since the intermediate shell 1 is placed on the philtrum, the distances between the nostrils and the oral cavity and the philtrum are different, and in actual applications, the oral air outlet center will have relative fluctuations relative to the philtrum. Therefore, the oral-side long hose 26 on the oral detection part 22 is longer, so as to facilitate the adjustment of the relative position of the oral-side long hose 26 during the actual detection process.

[0050] Embodiment 2:

[0051] like Figure 6 As shown, different from the embodiment 1, in this embodiment, a connection hole 24 is formed between the nose-side annular hose 23 and the intermediate shell 1, and the connection hole 24 can be detachably connected to the nasal oxygen tube 5. The connection hole 24 is formed in the middle of the nose-side annular hose 23, and the connection hole 24 can be detachably connected to the nasal oxygen tube 5. At the same time, due to the plastic deformation characteristics of the soft lead 2, it can be bent upward, and the entire sensor forms an "L"-shaped structure, thereby ensuring that the nose detection part 21 and the nasal oxygen tube 5 can work at the same time.

[0052] The assembly and working process of the oral and nasal thermal airflow sensor in this embodiment are as follows: In this embodiment, the sensor is in a state of being assembled with the nasal oxygen tube 5. In this embodiment, an intermediate shell 1 is provided, and a soft lead 2 is provided on the intermediate shell 1. In this embodiment, the soft lead 2 is a continuous line, which passes through the intermediate shell 1 in sequence after repeated bending, and forms a nose detection part 21 and an oral detection part 22. In this embodiment, the nose detection part 21 includes two nose-side annular hoses 23, and a connecting hole 24 is formed between the nose-side annular hose 23 and the intermediate shell 1. In this embodiment, the nose The side annular hose 23 is bent upward relative to the intermediate shell 1, so that the nasal oxygen tube 5 can pass through the connecting hole 24 to connect with the nostril, so that the nasal oxygen tube 5 and the sensor can work together. At the same time, because the side annular hose 23 of the nose does not penetrate into the nostril, it will not further increase the foreign body sensation in the nose on the basis of the patient's insertion of the nasal oxygen tube 5. In this embodiment, the nose detection part 21 is provided with two side annular hoses of the nose 23, and each side annular hose of the nose 23 is provided with a near-middle portion 25 in position, which means that the two side annular hoses of the nose 23 are close to each other. The detection unit 3 is provided on the near-middle portion 25. In this embodiment, The detection unit 3 in the embodiment is a thermistor, and the thermistor is arranged near the middle part of the proximal part 25, and is not arranged at the end, so as to avoid interference when the nose side annular hose 23 is bent. In this embodiment, the sensor is used in conjunction with the nasal oxygen tube 5, and the two proximal parts 25 can be bent to the middle position according to the actual condition of the patient, so as to adapt to a smaller size of the nasal oxygen tube 5, wherein two nose side annular hoses 23 are provided, and the oral side long hose 26 on the other side is connected to the two nose side annular hoses 23 at the same time, so the oral side long hose 26 is arranged between the two nose side annular hoses 23. In the embodiment of the present invention, only one oral side long hose 26 is provided, the oral side field hose passes through the intermediate shell 1 and is connected with the nose side annular hose 23, and a detection unit 3 is provided on the side of the oral side long hose 26 away from the intermediate shell 1, and the detection unit 3 here is also a thermistor, wherein the intermediate shell 1 is placed on the philtrum, and the distances between the nostrils and the oral cavity and the philtrum are different, and in actual applications, the oral air outlet center will fluctuate relative to the philtrum, so the oral side long hose 26 on the oral detection part 22 is longer, so as to facilitate the adjustment of the relative position of the oral side long hose 26 during the actual detection process.

Claims

1. An oral and nasal thermal airflow sensor, characterized in that: The invention comprises an intermediate shell (1), the intermediate shell (1) being connected to a soft lead (2), the soft lead (2) being provided with a detection unit (3), the intermediate shell (1) being connected to a transmission unit (4) which is in communication with the detection unit (3), the soft lead (2) and the intermediate shell (1) being connected to form a ring structure.

2. The oral and nasal thermal airflow sensor according to claim 1, characterized in that: The soft lead (2) comprises a nose detection part (21) and a mouth detection part (22), and the nose detection part (21) and the mouth detection part (22) are respectively arranged on both sides of the intermediate housing (1).

3. The oral and nasal thermal airflow sensor according to claim 2, characterized in that: The soft lead (2) is bent and passed through the intermediate housing (1) to form a nose detection portion (21) and a mouth detection portion (22); the nose detection portion (21) and the mouth detection portion (22) are integrally formed.

4. The oral and nasal thermal airflow sensor according to claim 1, characterized in that: The intermediate shell (1) comprises a fitting curved surface (11).

5. The oral and nasal thermal airflow sensor according to claim 1, characterized in that: The soft lead (2) comprises a nose detection part (21), the nose detection part (21) is provided with two nose-side annular hoses (23), and each of the nose-side annular hoses (23) is provided with a detection unit (3).

6. The oral and nasal thermal airflow sensor according to claim 5, characterized in that: A connection hole (24) is formed between the nose-side annular hose (23) and the intermediate shell (1), and the connection hole (24) can be detachably connected to the nasal oxygen tube (5).

7. The oral and nasal thermal airflow sensor according to claim 5, characterized in that: The nose-side annular hose (23) includes a proximal portion (25), and the detection unit (3) is arranged on the proximal portion (25).

8. The oral and nasal thermal airflow sensor according to any one of claims 1 to 7, characterized in that: The soft lead (2) includes an opening detection portion (22), the opening detection portion (22) includes an opening side long hose (26), and a detection unit (3) is provided on the side of the opening side long hose (26) away from the intermediate housing (1).

9. The oral and nasal thermal airflow sensor according to any one of claims 1 to 7, characterized in that: The transmission unit (4) is arranged at the end of the intermediate housing (1), and the arrangement direction of the transmission unit (4) is staggered with the arrangement direction of the soft lead (2).

10. An oral and nasal thermal airflow sensor according to any one of claims 1 to 7, characterized in that: The intermediate shell (1) is a color-changing shell; or / and the soft lead (2) is a color-changing lead.

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