Pressure Switch Low Switch Type SPST Switch Action Opens On Low Pressure Range (PSI) 0.3-150 Close (PSI) 20 Open (PSI) 5 psi Differential Pressure (PSI) 5 to 20 Auto Reset 1/4 in Female SAE Pressure Connection Capillary Length (In.) 18 in Universal NEMA 1 To Protect the Compressor Loss of Refrigerant in Commercial Refrigeration and Air Conditioning Systems Application For Refrigerants R 12 R 22 R 134A and R 502 In Commercial Refrigeration