Extech 40180 Tone Generator and Amplifier Probe KitExtech 40180 Tone Generator and Amplifier Probe Kit Tone Generator and Amplifier Probe Kit Heavy duty kit with audible tone Easily identifies wires and cables Key Features: Insulated inductive probe prevents shorting conductors Tests wire trace, continuity test, clear busy ringing line test and tip ring identification Alligator clips for non terminated cables and modular connectors for direct connections to telephone and internet wiring Built in