This is a new dual tube Mechanic StethoscopeExcellent Engine Analyzer Troubleshooter Locates Source Of Engine Noise Quickly28" in total lengthWith an audible tone, you can settle the problems much easiler by Tracing Sound of Flowing Water, Oil, Gas Or Steam with such Engine Tester Tool; Mechanics Stethoscope Automotive Engine Diagnostic Troubleshooter Tester is used to Identify Piston Slap, Worn Gears, Faulty Valves, Water Pump Failure, Damage Gaskets and Defective Bearings.Material:Plastic+metalpackage content1 x Mechanics StethoscopeNote:Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.