This tool is useful to test for a diagnoses of failed or leaking valves, pistons, rings and gaskets. A large gauge indicates percentage of leaking rather than psi. The constant supply of compressed air allows faults to be pin-pointed also by listening the leakage. The packaging includes: a gauge, a M14-M18 flexible threaded adaptor, two reductions M12-M10 and one extension connection. User instructions included.