Product Introduction: Durable Material: The car battery tester is made of plastic and metal, strong and practical, fine workmanship and good performance, durable for long time use Provides a convenient and intuitive way to diagnose, saving time and economy Uses 12V Power Supply: The car battery must be a 12V battery and the battery voltage is between 11V and 15V V. Ideal for coil resistance greater than 20 ohms. Test to correctly control the opening and closing of the relay. Easy to Use: Small size and compact structure, easy to carry and use. You can try it wherever you like. When the relay is abnormal, the red LED will light up, it is normal for the green LED to light up. Wide Application: The tester observes the data of contact, closing time, relay inertia at each test step, etc. The quick and easy automotive relay test provides a convenient and intuitive way to diagnose. This tester is used to test the status of your automotive relay < br/> Description: It is a quick test device