It need extra order one 9v battery, like  Wincell 9194 9V

Test correspondingly double-twisted cables 1, 2, 3, 4, 5, 6, 7, 8 and Ground
Capable to judge wrong connection, short circuit and open circuit
Cable Tester for RJ11, RJ12, RJ45, Cat 5e, Cat 5, 10/100 Base-T, AT&T 258 A, TIA-568A/568B .etc
It can easily clarify cable, continuity, open and short.
Verifying Cable continuity, open, short and cross wire pair up to 1000ft with remote kit.
9 LED lights to indicated wiring connection on both remote and master unit
Auto scanning function for rapid testing.
Grounding Test
Build in power switch for power saving
Operate with one 9V battery ( Not Included )
Size: 105 x 100 x 25mm
Weight:118g

Main tester
Size: 105*67*28mm
Weight: 74g
Remote tester
Size: 105*38*28mm
Weight: 47