Steelman TracerEAR Noise and Vibration Detection System gives a full range of sound, with no missing frequencies, to pinpoint noises and locations of worn bearings & bushings, noisy valves & lifters, broken or worn gear teeth, faulty fuel injectors, wind or air leaks, and annoying squeaks and rattles. This TracerEAR system features an ultra-sensitive microphone and amplifier, operating on a 9V battery (included), and the included headphones isolate sounds so that no unwanted noise bleeds in. The non-conductive microphone will not zap expensive computer circuitry, and a flexible shaft is also included to reach the tightest areas, all included in a carrying case.