[Easy to Use] This cable tester can quickly and easily find breakpoints without opening the wire cover. Audio signals are received through cables or wires (telephone lines). Tells you the status of your phone line, such as idle, ringing or busy Safely inspects cables without disturbing cable installations Sensitivity TestThe MS6812 cable finder is equipped with a very loud horn. Even though the tester is noisy, it can trace the cable more closely and identify cable problems. Determine the status of the business phone line (cut, ringing, busy). [High Quality] This wire tester has a sensitive sensor module that can quickly detect and respond to problems of the work circuit. Easily install, commission and maintain one or more telephone lines around your home or office with this high quality tracing system [Function] Robot Lawn Mower Wire Detector can check wire continuity and detect short circuit, open circuit and cross state testing. 3000m effective detection distance. Simple and easy to use. [Packing list] 1*transmitter, 1*receiver, 1*user manual, 2*battery. Product Sensitive sensor module The cable tester has a sensitive detection module that checks wire continuity and detects short, open and crossover condition testing . range Internet cafe hotel neork computer room power supply maintenance monitoring installation neork line engineering Does not damage the insulation Cable detectors detect the passage of cables or wires without damaging the insulation. Check cable continuity. Locate cables or wires and diagnose break points.