This instrument is designed to identify and trace wires or cables without damaging the insulation, you can also use it in checking for short circuit and locating open circuit and so on. In addition, it can also be used to identify some states of telephone line so that it is more convenient to install, debug, and maintain telephone lines, There are a Sender and a Receiver included in the instrument Provides an adjustable volume control Compatible with all common tracing tone sources Easy cable connection with either RJ-45 jack, patch cord, or alligator clips Features: Test the continuity of cables or wires Trace the cables or wires and diagnose the break point Identify the state in the working telephone line Transmit a single or alternating tone acro cables or wires and receive signal with tone probe Adjustable audio on tone probe Includes RJ11 jack for telephones and alligator style clips for wires Heavy-duty design for years of trouble free use Includes nylon storage case Specifications: Testing polarity of phone lines Tracing a wire Finding wires buried behind drywall Test whether a cable is interrupted Find interrupts in cableuit Power:9V battery (Not Include) Package Including: 1 x Cable Tracker Note:This item come without retail box,but we will pack well before shipping!