Differential Cylinder Compression Pressure Tester (18MM) 2E

Comes complete with on-off safety valve to eliminate pressure when disconnecting from the cylinder. Can be used to check intake or exhaust valves, cracked or worn rings, defective cylinders, worn bushings, etc. Specifications: Orifice size is .040". precision gauges matched to within +/-2%. Includes 18MM Spark Plug Adapter, 24" pressure hose, and complete instructions. Factory calibrated. For use with engines of 5" Bore Diameter or smaller