Tracer Products'TracerlineMarksman II, No. 9367, ultrasonic diagnostic tool converts and amplifies inaudible ultrasonic sound into audible "natural" sound. The user hear sounds that signify problems such as air brake leaks, compressed air leaks, vacuum leaks, tire leaks and much more before they lead to major breakdowns. The tool's Sound Signature Technology finely tunes the audible sound into the natural sound emitted by the leak itself. The tool's 5-LED signal-intensity indicator and audible alarm easily pinpoint the exact problem source. It can detect leaks from orifices as small as 0.004" (0.1 mm) at 5.0 psi (34 kPa), from a distance of 12" (30 cm).