Cable tracers are designed to identify and trace wires or cables within a group without damaging the insulation. This telephone cable tracing system consists of a tone generator and probe that allows you to find where the cable is routed and if (and if so where) there are any breaks in the line . It can also identify the status of a working phone line so you can determine if the line is idle ringing or connected all without any interference or damage to the cable installation. advantage: Determination of cable or wire continuity Breakpoint tracing and diagnosis Send a single pure tone to the cable Tells you the status of an idle ringing or busy phone line Safely inspect cables without interrupting cable installation High quality tool with volume sensitivity control Ready to use - just plug in the battery and youre done Easily install commission and maintain one or more telephone lines around your home or office with this high quality tracking system specification Net weight: 0.33 kg with battery 0.26 kg without battery Single package size: 26 x 12.5 x 4 cm Power supply: 2 x 9V batteries (delivered without batteries) Connector: RJ-11 (for telephone jack) Includes: transmitter receiver test leads carrying bag and instructions