... free, piston type; No air polluted. 3) Double air pressure switch. Product Name: Double Cylinder Airbrush CompressorModel AS19Brand HSENG Features1 ... pressure adjustor and pressure gauge. 4) Double air pressure switch.Switch 1, low pressure switch, for airbrush purpose.Switch 2, high pressure switch, for other high pressure ... 5x26.5CertificateCE, GS, ROHS, ETL, CETL haosheng Mini Air Compressor AS19