This instrument is a multifunctional handheld cable testing tool. Work perfect when RJ11 RJ45 cable is on power. It has a wide application with reinforced cable types and multiple functions. It is a necessary testing tool for telecommunication engineering, wiring engineering, and network maintenance person. Features: Wire tracing Trace RJ11, RJ45, cables or other metal wire (via adapter). Easy and fast to locate the breakpoint without opening the cover of wire. Network cable collation: judge short-circuits, breaking circuit, open circuit and crossing. Test cable level, positive and negative polarity. Status of telephone line checking: test the working status of telephone line (idle, ringing, and off-hook) and judge TIP and RING line. This handheld cable testing tool can check wire continuity. Specification: Brand: BSIDE Model: FWT11 Material: ABS Type: Measuring instruments Primary functions: Wire Line Finder Tracker Scope of application: Education,Home ,appliance,Industrial,Market,Office Operating temperature: 0 - 40, max. 80 %relative humidity (non-condensing) Storage temperature: -10 - 50,max.80 percent relative humidity (non-condensing) Altitude: