The B-3 & B-4 Pilot Operated Pressure Control Valves are factory assembled units. The unit consists of a J-2 Halar® coated Flow Control Valve, a Speed Control Valve, a C-2 Pilot Pressure Regulating Valve, and all the necessary trim. The Pilot Operated Pressure Control Valve is for use on wet sprinkler systems where it is necessary to reduce a higher inlet pressure to a lower delivery pressure and automatically maintain that pressure within a close limit, regardless of fluctuations in the higher pressure inlet line.