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: <2000m Anti-explosion rating: IP40 Distance of emitting signal: 300m or so Emitter battery: 6F22 / 9V (not included) Receiver battery: 6F22 / 9V (not included) Color: blue Emitter Size: 20*4*2.9cm/7.9*1.6*1.1in Receiver Size:12.5*6.5*3.2cm/4.9*2.6*1.3in Weight: Approx.252g/8.9oz Package list: 1 x FWT11 Emitter (battery not included) 1 x FWT11 Receiver(battery not included) 1 x Clip Adapter Cable 1 x RJ45 Adapter Cable .