Features: Can test telephone wire, network wire, power cable. Can test the line level, positive and negative polarity by using emitter only. Equipped with RJ11 cable and with BNC/RJ45 interface. Network wire checking function to judge normal/short-circuit/open-circuit/crossing and reverse connection. Easy and fast to locate the breakpoint without opening the wire's cover. Includes low battery indication function. Protected by a bag, portable to carry. Specifications: Material: ABS Short Circuit/Open Circuit Detection: Yes Distance of the Emission Signal: >300m Altitude: less than 2000m Classification: IP40 Safety Class: IEC61010-1 600 V CAT III, pollution class II. Power Supply: Emitter: 1 * 9V 6F22 Battery; Receiver: 1 * 9V 6F22 Battery (both NOT included) Operating Temperature: 0~40C(32~104F), 80%RH Storage Temperature: -10~50C(14~122F), 80%RH