Extech 40180 tone generator and amplifier probe kit. Heavy duty kit with audible tone easily identifies wires or cables. Insulated inductive probe tip prevents shorting conductors. Tests include 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. Selectable continuous or variable tone generation. Built-in speaker on probe with sensitivity control.