Longacre Analog Engine Leak Down Tester - 12mmDesigned to help you get the most out of your engine, the Longacre Analog Engine Leak Down Tester is the perfect tool to help you determine when your motor is due for an overhaul. Its easy to use design lets you quickly check ring seals, valves, and even head gaskets from the outside. Using precise readings and rugged construction, this tester allows you to get consistent power and extend the time between costly teardowns. It comes with a 12mm plug