The FHG2J27CP 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 100 PSI. The switch has a 1/4 inch NPSF internal fluid connection and is suitable for use with a lower-horsepower motor with 1.5 HP or less. 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 and two 2-pole NC contacts open on rising pressure.