P74FA-10C Differential Pressure ControlSeries P74 measures the pressure difference between two sources: supply lines and return lines. A change in differential pressure will reposition the switching mechanism to cause corrective action of the supplementary control equipment. Product Specifications BRANDJohnson Controls CAPILLARY LENGTH FEET3 BELLOWS MATERIALBrass SWITCH ACTIONSPDT (Snap - Acting) PRESSURE CONNECTOR1/4 in. Flare Nut LIMITED WARRANTY YEARS1