Brand new heavy duty 3 phase 140-175 PSI air compressor, pressure switch, control valve with a four port connection manifold. The switch listed is a universal replacement pressure switch that replaces brands such as Furnas , Square-D, Condor and more. This switch is equipped with an unloader valve, on / off pressure control button, and a four port mounting manifold. The unloader equipped on this switch is used to unload the air pressure off the head of the compressor when the compressor shuts off, this way when it starts there is no pressure on the piston and the compressor is able to start load free.