FB21-1H pressure switch, high pressure switch, air switch(up to 250psi) . The sturdy construction of FB21 pressure switch is designed for the requirements of ... unloader valve equipped to prevent the compressor from starting under load.MODELMin ON (Cut-In)PSIMax Off(Cut-Out) PSIDifferential PSIFactory ... : 1Mpa =10bar,1bar = 14.5PSI, 1Kgf/cm2 = 14.2PSI pressure control switch(FB21)