Compression Tester with Flex Hose and Quick Disconnect comes with a 15-inch flex hose to allow access to all cylinders and a side release valve to permit multiple readings without removing tester. This includes metal quick disconnect coupler and 14-millimeter and 18-millimeter spark plug fittings. The gauge is 2.5-inch (64mm) in diameter with dual calibration (0-300 PSI / 0-21 kg/cm2).