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 continuityBreakpoint tracing and diagnosisSend a single pure tone to the cableTells you the status of an idle, ringing, or busy phone lineSafely inspect cables without interrupting cable installationHigh quality tool with volume sensitivity controlReady to use - just plug in the battery and you're doneEasily install, commission and maintain one or more telephone lines around your home or office with this high quality tracking systemspecificationNet weight: 0.33 kg with battery, 0.26 kg without batterySingle package size: 26 x 12.5 x 4 cmPower supply: 2 x 9V batteries (delivered without batteries)Connector: RJ-11 (for telephone jack)Includes: transmitter, receiver, test leads, carrying bag and instructions