This tester measures the ability of an engine cylinder to hold compressed air using shop air pressure and supplements a compression tester. Pinpoints bad valves, worn rings, cracked cylinder walls, and blown head gaskets. Furnished with rubber boots to protect gauges. Includes a precision regulator with a M14 adapter on a 26 in. hose assembly. Neatly arranged in a plastic box The 2-1/4 in. special gauge has one multicolored band for measuring low, moderate and high leakage, and a scale range from 0-100%. The second gauge is 2-1/4 in. and has a dual scale dial with ranges from 0-100 PSI and 0-7 bar, which allows the technician to monitor input airline pressure.