This MAYILON phone line finder can be used for a variety of cable installations, inspections, and maintenance, and can judge the function of the phone line under different conditions. It can also be used for the installation, troubleshooting, and maintenance of phone lines. Come and try it, it won't disappoint you. Features: It can be used to judge the continuity of cables or wires, and can also check the break point. It can receive the tone signal from cables or phone lines and identify the working status of the phone line (ready, ringing, busy). It can be used to identify the positive and negative poles of the power supply, and judge the presence or absence of sound. It can be used for direct connection to the object's cables or wires. Large speaker, loud sound, can be heard even in noisy environments, providing you with a better user experience. With an intelligence button and indicator light, it is simple and convenient to use. Specifications: Material: plastic Transmitting Tone Frequency: 1.5 kHz Receiving Frequency Range: 100 Hz to 300 kHz Power Supply: 6F22, 9V (not included) Receiver Size: 238 * 43 * 26 mm / 9.4 * 1.7 * 1.0 inches Transmitter Size: 145 * 35 * 25 mm / 5.7 * 1.4 * 1.0 inches Receiver Weight: 56g / 2.0oz Transmitter Weight: 64g / 2.3oz Package Size: 300 * 130 * 60 mm / 11.8 * 5.1 * 2.4 inches Package Weight: 261 g / 9.2 ounces Package List: 1 * Transmitter 1 * Receiver 1 * User Manual