SUITABLE FOR- This tool set can be used for all kinds of cable line installation, inspection and maintenance, and can assess the work of the telephone line in different states. This will prevent cable insulation from being damaged. CONVENIENT- Establish continuity of cable or wires. Trace cables or wires and diagnose breakpoint. MULTIFUNCTION - Receive tone signal on cables or wires (telephone line). Identify working telephone line status (clearing, ringing, busy). Send single sliding tone or double tone on object cables or wires. HUMANIZED DESIGN- Large rear speakers, loud sound, can also be heard in a noisy environment. Intelligence button and indicator light. 3000m effective detection distance. 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.