Phenix Industries 12mm-1.5 Male to AN -6 Male Check Valve Adapter Fitting For Bosch Fuel Pumps

Spring loaded one way check valve designed to thread directly into electric Bosch or FluidFlow Performance Fittings fuel injection fuel pumps. Can also be used with Pierburg's 7.21659.72.0 fuel pump if you use the adapter fitting that comes with the pump.

Check valves are normally sprung or have a hinged trap door, keeping constant pressure in one direction, allowing fluid to travel one way through the valve. Ideal to prevent drain back after the fuel pump is turned off, or when dual pumps are used and both pumps may not run simultaneously.