ALLOSUN EM285 Electric Circuit Tester Easy to use. Best electrical tester for reducing diagnostic time in Automotive electrical systems. Wide range applications. Can be used to test continuity, test polarity of a voltage, check Lamp, check electric motor, follow and locate short circuits, test for bad ground contacts etc. Long test lead. The cable length is about 5M which allows you test any electrical system easily. Safety insurance. When the current exceeds 8A, the Unit will disconnect the current automatically. Do not use on AC voltage. Please read the manual carefully before using the product. Test for continuity Test for polarity of a voltage Check lamp Check electric motor Power supply function may be selected Follow and locates short circuits Test for bad ground contacts Polarity testing Continuity testing Testing trailer lamps and connections Checking For bad ground contact Activating components out of the vehicle&#039;s electrical system