It is used to test RJ45 cables, RJ11 telephone lines and network cables.It can easily distinguish cable, continuity, open and short; Verify the cable continuity through the remote controller kit, open, short wire and crossover wire pair. Features - Material: PC. - Size: 10.20X9.50X2.70cm/4.01X3.73X1.06 inch. - Battery: 9V battery (not included). - Interface: RJ11/RJ45. - Cable tester for RJ45 ethernet network cables, and RJ11 telephone cables. - Correspondingly test double-twisted cables 1, 2, 3, 4, 5, 6, 7, 8 and ground. Keep your network running smoothly by testing wrong connection, short circuit and open circuit. - LED lights to indicate wiring connection on both remote and master unit. Easy read LED display which indicates problems. - Inserting the cables, this cable tester will run automatically, the LED light will display status, any troubleshoots such as the short circuit, open circuit, cross line ,can be found rapidly and easily. - Our RJ45 network cable tester is convenient to hold in hand for its mini size and it comes apart :master unit and remote unit.