Includes-amplifier rn/wc-1, headset rn/wc-2, detector rn/wc-3, magnet rn/wc-4, probe rn/wc-5, carrying case rn/wc-6; amplifier dimensions-5in. W by 7in. L by 3.5in. H; carrying case dimensions-7in. W by 8in. L by 8in. H; total weight 5lbs; used to detect exact movement of wheel or mandrel contact by audible signal