The ANENG Universal Car Relay Tester Voltage Tester RT01 11-25V is a versatile diagnostic tool designed for automotive use. It can test relays in vehicles such as motorcycles, passenger vehicles, and heavy-duty/commercial vehicles. The alligator clip has an opening size of 2.1cm/0.82inch and a length of 42cm/16.54inch, making it easy to securely connect to car battery power supplies. The device features a digital display for clear readings and has a unit type of unit. With a volt range of 12 volts, this tester is a reliable tool for troubleshooting automotive electrical systems.