This practical new type of device deals with the domain of water treatment technology. It is a device that prepares water of small molecular groups in various polymerization forms under varied operation conditions. It is applicable to various fields including planting, human health care, bio-engineering, descaling of thermal systems and printing and dyeing in textile industry. The new type has these features: The magnetizer is installed in the inner core, and the permanent magnet is installed in the magnetizer; Its advantages are: The structure is fresh, the adaptability is wide, the function is multiple, and the effect is stable and evident (for example, in vegetable growing, the yield of the various vegetables irrigated by the active water increased by 30%-103%).