SUITABLE FOR- This tool set can be used for all kinds of cable line installation, inspection and maintenance, and can assess the telephone line work in different states. This will prevent the cable insulation from being damaged. CONVENIENT- Establish the continuity of the cable or wires. Trace the cables or wires and diagnose the point of failure. off. MULTIFUNCTION- Receive tone signal on cables or wires (telephone line). Identify working telephone line status (clearing, ringing, busy). Send a sliding single tone or double tone on the cables or wires of the object. HUMANIZED DESIGN- Large rear speakers, loud sound, can also be heard in a noisy environment .Intelligence button and indicator light.Effective detection distance of 3000m. EASY TO USE - Not only rich in functions, this cable finder is also very easy to use, and it will be a good helper for you.