Total Seal cylinder leak down tester quick diagnoses failed or leaking valves, pistons, rings, head gaskets. Calibrated for high accuracy and repeatability. Has a dual gauges indicates percentage of leakage rather than PSI, eliminating the need for math calculations a comes with a hose with quick coupler disconnect fitting and adapter 14mm spark plug. A small air compressor with minimum of 100 psi is required to do the test. Please e-mail with questions.