A tone generator and amplifier probe kit is the Extech 40180. This robust kit makes it simple to identify wires or cables with its audible tone. Conductor shorting is avoided by the insulated inductive probe tip. include tip or ring identification, a wire trace, a continuity test, and a clear/busy/ringing line test. comprises a casing, RJ45 and RJ11 modular connectors, alligator clips, and a 9 V battery.