The Extech 40180 is a Tone Generator and Amplifier Probe Kit. This heavy-duty kit with audible tone easily identifies wires or cables. The insulated inductive probe tip prevents shorting conductors. Featuring a wire trace, continuity test, clear/busy/ringing line test, and tip or ring identification. Includes alligator clips, RJ45 and RJ11 modular connectors, 9 V battery, and a case.