The cable tracker is designed to identify and trace wires or cables within a group simply by attaching the sender to the cable at one end and then touching the cables at the other end with the receiver to confirm which is the correct cable, without damaging the insulation. -For telephone line, it can identify some states in the line, and can help to install, debug, maintain telephone line. -Send a single solid tone or dual alternating tone to the object cables or wires. -A professional & safe tool for wireman. Package: 1 x Cable tracker sender 1 x Cable tracker receiver 1 x User manual 1 x zip-up Tool Pouch.