Includes air regulator, 0 - 100 PSI pressure gauge, plugs for water and oil cooled oil pumps, gasket and needed hardware Only fits FeulingÖ oil pumps, will not work with factory Harley-Davidson oil pumps The spring tension can be adjusted to achieve the desired pop off PSI Allows the engine builder to know what PSI the relief valve opens FeulingÖ oil pump pressure test tool for FeulingÖ M8 oil pumps Made in the U.S.A.. TOOL RELIEF VALVE CAMPLT