Features: Upgraded Function: with red light pen function to detect optical fiber on and off. Line Hunting Function: it can be used for RJ11. RJ45 interface cable hunting, and other metal wires can be hunted through an adapter. Find Cable Breakpoints: no need to strip the line insulation skin, simple, fast, convenient, and can quickly identify the location of the line breakpoint. Find the Short-circuit Point of the Cable: it can accurately find the short-circuit position of two cables. Check the Alignment: measure whether the wiring sequence of the crystal plug of the network cable is correct. Battery Indicator: when the battery is under-voltage , the power-on button flashes to indicate insufficient. Receiver NCV: can be used for non-contact AC voltage detection above 48V. Receiver Lighting: can be easily used in a darker environment. Receiver Signal Attenuation Knob: it can be used for tracking, breakpoint, short-circuit point, signal strength adjustment and precise positioning. Receiver Earphone Jack: plug in headphones in a noisy environment to avoid external noise from interfering with the measurement. Wide Application: necessary testing tool for telecommunication engineering, internet bar, network maintenance, professional wiring, electricians, etc. Specifications: Material: ABS Red Light Pen Function: 5mW power, 300m Safety Level: IEC61010-1 600V CAT III, pollution class II Working Temperature: 0~40& 8451;, maximum relative humidity of 80% Storage Temperature: -10~50& 8451;, maximum relative humidity of 80% (remove batteries) Power Supply(NOT Included): Emitter: 1 * 9V 6F22 battery, Receiver: 1 * 9V 6F22 battery Emitter Size: 140 * 60 * 25mm / 5.51 * 2.36 * 0.98in Receiver Size: 190 * 40 * 23mm / 7.48 * 1.57 * 0.91in Emitter Weight: 82g / 2.89oz Receiver Weight: 81g / 2.86oz Package Weight: 372g / 13.12oz Package Size: 22.5 * 14 * 4.5cm / 8.86 * 5.51 * 1.77in Packing List: 1 * Emitter 1 * Receiver 1 * Pair of Earphone 1 * RJ11 Clip Adapter Cable 1 * RJ45 Cable 1 * Storage Bag 1 * User Manual (English)