LockNLube LNL81300 D Pressure Return Valve for DeWalt Cordless Grease Guns deep tray To be used either in caliper tool To be used either in CNC machines or hand held routers head heightSTRONG: Impact ready for the strength to stand up to the power of today's impact driversONE HANDED USE: Rare Earth magnet retains fastener for easy one handed useDURABILITY AND CONVENIENCE: Metal gearcase with quick bit ejection adds durability and convenience to any jobsiteCOMFORT AND CONTROL: Patented handled designed (Flexshaft and modular handle) to reduce vibration this innovative valve allows operators to return built up pressure and trapped grease from the hose directly back into the barrel with a simple twist of a knob By eliminating the high pressure backflow that occurs when a grease fitting is clogged