Perfect for installing, debuging, maintaining telephone line and other wires or cables. Detect continuity of the cables or wires without damaging the insulation Track the cables or wires, and diagnose the break point. Receiver the tone signal on the cables or wires (telephone line). Identify the state in the working telephone line (clear, ring, busy). Send a single solid tone or a dual alternating tone to the object cables or wires. A professional & safe tool for wireman. Battery Type: 2 x 9V batteries(No Battery) Material: plastic colour: green Package Contents: 1 x Sender 1 x Receiver Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.