Greenlee 77HP-G/6A Tone Generator for VDV Cables sends signal via wires or pairs from one end of a cable to another one, in order to help techs or cable installers to identify individual wires in a bundle. This is a classical tone generator originally designed by Progressive Electronics, a very durable product and an industry standard. Greenlee 77HP-G tone generator is widely used to trace datacom, telecom, security and CATV wires and cables, as well as de-energized AC wiring. The 77HP-G/6A test leads are equipped with bed-of-the-nails aligator clips.