describe: 12V Electric Vehicle Relay Tester Battery Diagnostic Tool Bayonet Relay Tester. CNBJ-707 is a quick test tool for testing automotive relays, so you can check the status of automotive relays. By connecting the car's continuous battery (11V-15V) to the relay coil, the tester can properly check the contact function of the relay. Testers observe contact data, closing time, relay inertia, etc. during each test phase. If the test passes, the green light is on; if the test fails, the red light is on. Features: This tester is designed for testing the status of automotive relays. Test to properly control the opening and closing of the relay. If the relay is abnormal, the red LED will be on, which is normal, and the green LED will be on. Provides convenient and intuitive diagnosis, saving time and money. Small size, compact structure, easy to carry, can be tested anytime and anywhere. Specification: Voltage: 12V Material: plastic and metal Color: black and red Product size: about 12*6*2.5cm/4.72*2.36*0.98 inches Product Weight: Approx. 180g/6.35oz Package size: about 15*8*5cm/ 5.91*3.15*1.97 inches Package Weight: 200g/7.05oz packing list: 1*Relay Tester Notice: The car battery must be a 12V battery and the voltage must be between 11-15V. The coil resistance is preferably at least 20 ohms.