This Sunny SU-H4 air-compressor pressure switch controls an electrically driven air compressor in a power circuit when the adjustable threshold upon falling is reached and is set to turn off at 175 psi. The switch have four 1/4" NPSF internal fluid connection. The adjustable cut-out range is 60-200 psi. The switch is diaphragm actuated and has a fixed differential. The threshold, or setting point, upon rising adjusts with a screw nut. The switch has screw terminal electrical connections. The maintained manual cut-out lever has auto and off positions.