Description: This is a fast test tool to test automotive relays, so that you know the status of automotive relays. Through the continuous automobile battery (11V-15V) to the relay coil, the detector can properly check the relay contact function. The tester observes contact data, closure time, relay inertia at each test stage, etc. If the test is qualified, the green light will be on, and if the test is not qualified, the red light will be on. Test to properly control the opening and closing of the relay. If the relay is abnormal the red LED will light, it's normal the green LED will light. Provides a convenient and intuitive diagnostic way, time-saving and economical. Small size, compact structure, easy to carry, you can test anywhere as you want. Note: Car battery must be 12V battery, the voltage must be between 11-15V. The coil resistance is preferably at least 20 ohms. Specification: Voltage: 12V Material: Plastic & Metal Color: Black & Red Item Size: 13X7X3cm Package Includes: 1X Relay Tester Note: Conversion: 1inch=2.54cm, 1cm=0.393inch Please allow slightly 0-1cm difference due to manual measurement. Colors can appear different depending on light and how the listing is viewed. Thanks for your understanding and attention. Wish you a pleasant shopping experience!