125 PSI, Air-Compressor Pressure Switch, Controls An Electrically Driven Air Compressor In A Power Circuit When The Adjustable Threshold Upon Falling Is Reached & Is Set To Turn Off At 125 PSI, Switch Has A 1/4" NPT External Fluid Connection & Is Suitable For Use With A Higher-Horsepower Motor With 2 HP Or Greater, Non-Adjustable Differential Is 40 PSI & The Adjustable Cut-Out Range Is 100-200 PSI, Switch Is Diaphragm Actuated & Has A Fixed Differential, Threshold, Or Setting Point, Upon Rising Adjusts With A Screw Nut, Has Screw Terminal Electrical Connections & Two 2 Pole NC Contacts Open On Rising Pressure, Includes A 2 Way Pressure Release Valve, Maintained Manual Cut Out Lever Has Auto & Off Positions.