Allows the engine builder to know what psi the relief valve opens the spring tension can be adjusted to achieve the desired pop off psiTool includes:Air regulator0-100 psi pressure gaugeGasket and needed hardwareMade in the USAFeuling® recommends the cam plate valve be seated 0-30 psi with full pop off at 55-60 psi.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.Camplate psi tester fits all Twin Cam camplates factory and aftermarket, '07-'17 camplates will have 1 un-used bolt hole.EU: Feuling® recommends the cam plate valve be seated 0-2,06 bar with full pop off at 3,79 bar - 4,13 bar.