Features: 100% brand new and high quality Judging whether the continuous cable line. Tracking cable line, and the discrimination of the circuit breaker points. Receiving the cable lines (telephone line) of the audio signal. The telephone line to judge the work in the state (idle, ringing, off hook). The transmit audio signal to the target cable line. Specifications: Power supply Receiver: 9V 6F22 Battery (not included) Transmitter: 3 * 1.5V AA (not included) Receiver: 21.4 * 4.5 * 2.9 cm / 8.5 * 1.8 * 1.15 in Transmitter: 12.4 * 6.6 * 3.1 cm / 4.9 * 2.6 * 1.2 in Package size: 23.7x14.2x5.1cm Package included: 1 * Headphone 1 * RJ11 Telephone Cable 1 * Tester Clip from Terminal 1 * English User Manual 1 * Storage Bag