Professional tool for commercial or occasional use. Dual tube mechanic stethoscope. Excellent engine analyser trouble-shooter locates source of engine noise quickly. With an audible tone, you can settle the problems much easier by tracing sound of flowing water / oil / gas or steam with this tool. Used to identify piston slap, worn gears, faulty valves, water pump failure, damage gaskets and defective bearings. 2 piece metal probe extends another 8" (so a total of 113/4") (29.85cm) for hard to reach spots. Super sensitive ear pieces and probe. Plastic handle with heavy duty flexible vinyl tubing. Shockproof abs handles.