1. 100% Brand new and high quality! 2. Wire Tracing: Trace RJ11, RJ45, cables or other metal wire (via adapter). 3. Easy and fast to locate the breakpoint without opening the wire's cover. 4. Network cable collation: Judge short-circuit, breaking circuit, open circuit and crossing. 5. Test line level, positive and negative polarity. 6. Status of telephone line checking: Test the working status of telephone line (idle, ringing, and off-hook) and judge TIP and RING line. 7. Check wire continuity. 8. Work profect when RJ11 RJ45 cable is on power1. TemperatureOperating temperature: 0 °C ~ 40 °C, maximal 80% relative humidity (non-condensing)Storage temperature:-10~50°C, maximal 80% relative humidity (non-condensing, battery not included) 2. Altitude: