1Multifunctional circuit tester for voltage and polarity tests, continuity tests, signal circuit tests, power/activation components, trailer lights and connection tests. Test vehicle battery voltage, Ac and Dc voltage tests, resistances, leaks, short circuits, component activation overload protection with large battery clamp, etc., able to withstand greater loads. It supports a wide input voltage range of 9V?70V, can be used for 12V car and 24V trucks. 2Made of plastic materials, environmentally friendly and non?irritating. Low power consumption, high performance. Comes with a 10m/32.8ft extension cable allows you to test car or truck. 3Designed with an easy to navigate user menu, you can read Dc voltage, Ac voltage, resistance and diode parameters clearly. The Dc voltage mode is used to read the Dc voltage at a resolution of 0.1 volts; Ac voltage mode for reading maximum voltage, minimum voltage and frequency; The resistance mode is used to read the resistance between the tip and the auxiliary ground lead. 4With automatic circuit breakers, safe and sustainable to use, and short?circuit protection prevents overload of equipment. Before you start testing circuits or components, you must do a quick self?check to insure that your tool is in good condition. 5It can determine at a glance whether the circuit is positive, negative or disconnected without having to reconnect the clamp from one battery pole to another. By depressing the power switch, conduct a positive or negative battery current to the probe tip for testing the function of an electrical component without the use of jumper wires.