Universal Compatibility :This relay tester is compatible with all types of cars, making it a versatile tool for any car owner. Accurate Diagnosis:With its ability to test relays, this tool can help diagnose any issues with your car's electrical system. Easy to Use :The simple design of this tool makes it easy to use, even for those who are not experienced in car repairs. Color: red+black material: plastic Introduction: 1. Connect the power leads to the car battery --black alligator clip to negative terminal, red alligator clip to positive terminal. 2. Tester is powered up when the LED illuminates in RED. 3. Check the relay before plugging into the tester. If it's a 4 pin relay,select"4 pin" on the tester.If it's a 5 pin relay, select"5 pin"on the tester. 4. Plug in the relay into one of the three receptacles. 5. Press the "TEST" button. 6. Tester will check the pin configuration of the unknown relay. Tester will light the RED LED if the relay is not the same to the most of common automotive relaysor the pin of the unknown relay is destroyed. 7.Tester will open and close the relay 10 times for testing the time to contacts closure and opening if the pin configuration of the relay is right. Tester will light the RED LED immediately if the time is overtime. 8. Tester will check the consistency of the relay after testing the time to contacts closure and opening ten times. Tester will light the GREEN LED if the test passed, if not light the RED LED. 9. Disconnect power leads from the car battery and remove relay from the tester. Attention: 1. The car battery must be 12V battery, and the voltage of the battery is among 11V-15V. 2. perfect for coil resistance above 20 ohms. Package Contents: 1x Car Relay Tester Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.