Water Pressure Relief Valve 3/4" NPT Male X 1/2" NPT Female 

Adjustable  Water Pressure Relief Valve 3/4" NPT Male Port, 1/2" NPT Female Port

This spring loaded adjustable water pressure relief valve is perfect for bleeding off excess engine water pressure caused by pressure spikes in an engines cooling system.  water flows freely when water pressure exceeds the set designated pressure.  Keep high pressure spikes from damaging your engine.

Adjustable from 7-25 PSI. Flow rate: 1.5 GPM at 10 PSI, 5 GPM at 25 PSI.