This tool set can be used for all types of cable line installations, d=inspection and maintenance, and can judge the work of the telephone line in various states, more convenient for telephone line installation, debugging and maintenance work. It allows you to prevent damage to the insulation of the cable. Features: Judges the continuity of the cable or wires. Track the cables or wires and Diagnose the break point. Receiver, the tone signal on the cables or wires (telephone line). Indentify the working telephone line status (clear, ring, busy). br/> Send a single solid tone signal slide or a double alternation tone to the object cables or wires. Rear speakers large, large noise, in a noisy environment can also be heard. Inteligence button and indicator light. 3000m effective detection distance. Easy and convenient to use. Features: Send tone frequency: 1 .5kHz Receive frequency range: 100 Hz-300 kHz Power supply: 6F22, 9V (not included) Receiver size: 238 * 43 * 26mm / 9.4 * 1.7 * 1.0in br/> Transmitter size: 145 * 35 * 25 mm / 5.7 * 1.4 * 1.0in Receiver weight: 56g / 2.0 oz Emitter weight: 64g / 2.3 oz Shell color: green Package size: 300 * 130 * 60 mm / 11.8 * 5.1 * 2.4 In Package weight: 261G / 9. 2 oz Package List: 1 * Transmitter 1 * Receiver 1 * Instructions