PA VB 350 S Pressure Regulating Unloader Valve (discharging) With Max. and Min. Pressure Adjustment. At gun shut off, the water flow is bypassed at reduced pressure. Assembly equipped with a high pressure proof compensation. Compact dimensions. Sturdy steel and brass construction. Fixing system for the max. and min. pressure. Sst seat for check valve, replaceable. Nylon knob. By-pass G1/2 F. Easy maintenance.