Easily detect faulty networks and phone lines with RJ45 and RJ11 connections using this network cable tester. Connect one end of the cable to the main unit, the other to the detachable remote unit, and turn on the power. The unit's LED's can be used to see how the cables are wired, to identify short circuits, incorrect wiring, or crossover connections. Main unit requires one 9V PP3 battery (not supplied).Battery[tab]1x 9Vdc PP3 (not supplied)[br]Dimensions[tab]100 x 100 x 28mm[br]Weight[tab]90g (without battery)[br]Connections[tab]RJ45, RJ11