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