These Actron compression test kits are designed to detect worn piston rings, burnt valves, and blown head gaskets. They feature a push-button side release valve, which allows you to repeat testing the cylinder without disconnecting the tool. The kits include a full 2 1/2 in. easy-to-read gauge that measures 0-300 lbs. psi, 17 in. high pressure flexible hose, and both 14mm and 18mm spark plug adapters.