Bench test cam plate before installation, cycle the pressure relief valve, testing operation and assuring the valve moves freely, seats and seals each time, any leakage at the relief valve will reduce oil pressure This tool allows the engine builder to know what PSI the relief valve opens; the spring tension can be adjusted to achieve the desired pop off PSI Cam plate PSI tester fits all Twin Cam cam plates Made in the U.S.A. Tool includes: Air regulator 0-100 PSI pressure gauge Gasket and needed hardware Feuling« recommends the cam plate valve be seated 0-30 psi (EU: 0-2,06 bar) with full pop off at 55-60 psi (EU: 3,79 bar - 4,13 bar).. TOOL,RELIEF VALVE POPOFF