The sensor of the switch is piston type and diaphragm type combination. Can be used to control the compressed air which contains oil mist and other gas which contains oil mist which will not exert corrosion to sensor material and hydraulic oil, water-oil mixture corrisve liquid and neutrial liquid medium with good lubricating property. the Set Point is adjustable ,the adjustable range is from 0.3 to 40 Mpa.