6-12V DC High/Low Tester, use on 12V DC automotive circuits to determine if the circuit is live, simply clip the insulated alligator clip to the frame of a vehicle and plug the other end into the tester, pierce the Steel tester point through the wire insulation of a live 12V DC circuit, if the bulb in the tester illuminates, the circuit is live. Circuit, Handle The tester is tinted to see the bulb illuminated in the light of the sun, with 3 W bulb, tinted handle, 6-12 V DC perforated wire.