Vastar Network Cable Tester RJ45 RJ11 RJ12 CAT5 CAT 6 Multi-Functional UTP Network Cable Test Tool, Cable Lan Analyzer The network cable tester used for testing rj45 cables, rj11 telephone cables and network cables Small and easy carried with smooth lines which is designed drop prevented and portable hand-held Note: The cable tester can be only used with a certificated 9v battery Easily switch between slow automatic grade and manual grade, easy to read led display which indicates problems Keep your network running smoothly by testing wrong connection, short circuit and open circuit