Monoprice RJ-11 and RJ-45 modular plug tester helps to troubleshoot network and telephone cables for broken wires and crossed connections. Monoprice RJ-11 and RJ-45 modular plug tester includes main master unit and a detachable remote unit. Tester is a simple yet powerful tool that supports both a fast automatic and a slow automatic mode. • Used to test broken wires and crossed connections. • Consists of a main Master unit and a detachable Remote unit each of which have an RJ11 and an RJ45 jack. • Simple yet powerful tool that helps troubleshoot network and telephone cables for broken wires and crossed connections. • Unit is powered with a 9 V battery and can be stored in the included zippered synthetic leather case. • Master and Remote unit each have a series of 9 LEDs that show the status of each line on-the attached cable. • Supports both a fast automatic and a slow automatic mode. • Includes 1 x cable tester master unit 1 x cable tester remote unit (attached to Master) 1 x synthetic leather zippered carrying case. • Sold as 1 Each.