1High Performance: The relay tester will automatically detect the pin position, the release time of the action, and the consistency of the relay in each test phase. 2Easy to Use: Check the relay before testing. Select the appropriate socket and insert the relay, press the "Test" button, and the tester will detect the pin position of the unknown relay. 3Diagnosis Indication: If the tester lights up the green LED light, the relay is normal, if the red LED light is on, the relay is abnormal. 4Fitment: When testing, it needs to be connected to the car's 11V?15V battery. The car battery must be a 12V battery, the coil resistance is preferably above 20 ohms. 5Compact: Small and easy to carry around for on the go jobs, allows easy use no matter where you are, give you the results you need quickly and easily.