Triplett / Byte Brothers CTX590 ProTone Probe and Tone Generator Wire Locator with Protective Pouch Locate cable runs by placing a tone on one end of the cable with the tone generator and detecting the tone on the far side with the tone probe Test for continuity (shorts) and the presence of voltage (AC, DC and polarity are indicated on live circuits) Switch selectable tone (steady or warbling) Probe's ultra bright LED lighted tip lets you see in dark closets Insulated tip stops accidental shorts when probing punch down blocks