Velleman VTLAN4 LAN TESTER FOR RJ45, RJ12, RJ11 LED indication advanced design for easy testing ability to test cables from a distance and in places that are not easily accessible automatically runs all tests and checks for continuity, open, shorted and crossed wire pairs slow and fast test switch tests: RJ-45, 10 Base-T, Token Ring, RJ11/12 cables power supply: 9V-battery (not incl.) max. cable length for testing: 984ft (0.18 mile)