This unit is the best electrical tester for reducing the diagnostic time of automotive electrical systems. After simply connecting the unit to the vehicle battery, an automotive technician can conduct positive or negative battery current to the tip by rocking the power switch forward or backward. The unit is short-circuit protected and can immediately test for poor ground contact. It allows you to track and locate short circuits. It can also test continuity with the help of its auxiliary ground wire. 4M long cable makes your testing easy. It is a comprehensive 6-24V DC test kit. Product name:Car circuit tester Operation voltage: 6-24V DC Cable length: about 4m Overload protection: 10A (When the current exceeds 10A, this item will disconnect the current automatically.) Applications: 1.Test for continuity 2.Test for polarity of a voltage 3.Check switches, relays and the on-off of diodes, fuses and circuits 4.Test for polarity of electric cables and plugs 5.Track and locate short circuits 6. Test for ground contacts Colour:black Material:plastic Package Contents: 1 x Car Circuit Tester Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.