The Triplett CTX590A ProTone Wire Locator Kit comprises a tone generator and a probe, both useful for tracking down shorts in circuits, for testing connections, and for locating wires. Its inductive probe senses a tone sent to the wires with the included tone generator, which offers RJ11, RJ45, and insulated alligator clip connections. Clips for all these connections are supplied with the unit. A red/green LED on the probe shows you the continuity, voltage, and polarity of the signal you're tracing. The probe also offers a sensitivity control. It ships with the aforementioned clips, the 9V batteries needed to power the probe and tone generator, and a case.