Longacre Digital Engine Leak Down TesterThe digital readout on Longacre's Digital Engine Lead Down Tester features large, easy to read numbers and is accurate to . 5% (1 2 of 1%). The easy to use tool checks rings, valves, and even head gaskets. The rugged design features rubber bumpers to protect the gauges, while the exclusive gauge manifold meters the airflow for precise readings. Backlit display for night use, and includes silver carrying case.