No damage insulation layer: The cable finder detects the passage of cables or wires without damaging the insulation..Check if the cable is continuous..Trace the cables or wires and diagnose the points of 'stop Check network cable and line function: receive audio signals via cables or wires (telephone lines)..Identify working phone line status (idle, ringing, lifting)..Send signal single or two-tone cableor target cable. Easy to carry: Small, light, easy to carry, long service life, low power consumption, compact and safe. It can be reused and is durable. Comes with a bag that can be stored well and prevents dust and collisions. Mulit-Function: Voltage Detector can also diagnose break point, receive tone signal on cables or wires (telephone line)