HDE RJ45 RJ11 RJ12 Cat5 Cat6 UTP Network Cable Tester for LAN Phone Wire Test Tool Construct your own patch cables? Test them with this! Works with Twisted-Pair, Straight & Crossover Cables: RJ-45 & RJ-11 This cable tester comes apart so you can test even when the cable's ends are in different rooms Requires one 9-volt battery (not included) Tester detects if wires are connected correctly; Includes travel case & instruction sheet