8 Pc Spark Plug Cylinder Compression Tester Test Kit Professional Gas Engine A complete test kit to check valves and rings, perform carbon build up inspection and test for late timing on a wide number of vehicles. Gauge with rubberized protector and dual color scale, tests up to 0-300 PSI and 0-20 kPa. Compatible with gasoline engines. Test from your own garage. Blow mold case included for easy storage.