Quickly tell - from the outside - when your engine needs an overhaul! This easy-to-use tester checks ring seals, valves, even head gaskets. Dont wait too long to rebuild that expensive motor, but dont do it too soon either! Allows the ability to achieve consistent power. Stretch out the time between costly teardowns. Rugged design features rubber bumpers to protect the gauges. Exclusive Longacre gauge manifold meters the airflow for precise readings.