Quality Air Compressor Pressure Switch Control 140-175 PSI 1 Port w/ Unloader Air Compressor Pressure Switches For all global air compressor and water applications. Diaphragm act Model SP-205 UL Listed and CSA Certified. DPST switch Rated 20A Temp. range: -22 to 257F ressure Switch, Air Compressor, Standard Action, Factory On/Off Set 140 to 175 PSI Port Type 4-Port 1/4 In NPT (Female), 1/4 In Compression Unloader