: Durable Material: The car battery tester is made of plastic and metal, sturdy and practical, fine workmanship, good performance and durable. Provide convenient and intuitive means of diagnosis, save time and money Use 12V power supply: The car battery must be a 12V battery with a battery voltage between 11V and 15V. The most suitable coil resistance is greater than 20 ohms. Test the controller to open and close the relays correctly Easy to use: small size, compact structure, easy to carry and operate. You can try it wherever you want. If the relay is normal, the red LED is on and the green LED is normal; allium Wide range of applications: The tester observes contact data, closing time, relay inertia, etc. at each test step. Quick and easy automotive relay test provides convenient and intuitive diagnostics. This tester is designed to test your car relay condition Note: The data is all measured manually, please allow 1-3cm error, due to the light and display difference, there will be some difference of color, the actual object received shall prevail.