Air preparation units also called air treatment units, or air preparation kits, include air filters, air regulators, and air lubricators, which can be used as a separate unit, or a combination. Flexible attachment by the brackets. The body material uses cast aluminum, with the metal protective shell or plastic shell. The installation of a pressure gauge has two ways, an add-on pressure gauge, or the built-in pressure gauge. A variety of series of air preparation units can replace SMC, FESTO, AIRTAC products perfectly.