The unloader valve diverts water flow into bypass when the trigger gun valve is closed. Unloaders may be designed to respond to either an increase in pressure or a change in flow. The unloader valve may also be used for variable pressure adjustment. Specifications: Max GPM- 10.5 Max PSI- 4500 Inlet- 2x3/8" F Outlet- 3/8" Max Temp- 194° F By-Pass- 2x3/8" F Spring Color- Black Knob- Yes