A tester uses to test the conductivity of pin lead wire used in T.E.N.S. units. Many clients report the malfunction of T.E.N.S. units is only due to the disconnection of pin lead wires. This tester helps people to test function of the wire before sending back the T.E.N.S. unit for repair. Both of the 2.5mm & 3.5mm plug can be tested by the tester.