This instrument is used to identify and trace wires or cables without damaging the insulation. It can also be used to test for short circuits and locate open circuits. It can also be used to identify specific telephone line conditions to simplify telephone line installation, debugging, and maintenance. The instrument includes a transmitter and a receiver Provide adjustable volume control Compatible with all common tracking audio sources Use RJ-11 jacks, jumpers, or alligator clips for easy wired connection Check cable or wire continuity Trace cables or wires and diagnose breakpoints Identify the condition on the business telephone line Transmit single or alternating sound through cables or wires and use audio probes to receive signals Adjustable audio on sound probes With RJ11 phone jack and alligator clip for cables for many years, trouble-free use Battery: 2 x 9V battery (without battery) Color: Yellow Material: ABS Size: 255 x 120 x 36 mm Package Contents: 1 * Cable Transmitter 1 *