Wide Application: Wide range of applications, suitable for most car lights, wipers, starters, air conditioning, electric seats, electric doors and windows, anti-lock brakes, audio relays. High Quality Material: The car repair tester is made of high quality ABS, light weight, wear-resistant and corrosion-resistant, suitable for use at long term. Excellent Performance:The tester checks the proper operation of the relay contacts by connecting the car battery (11V-15V) to the relay coil.Small size,compact structure,lightweight,easy to carry,can be tested anytime and anywhere. Indicator Light:Equipped with LED indicator, the test result can be easily detected. When the green light is on, the test battery is normal, and when the red light is on, the test battery is bad. Easy to Use: Simply connect the tester to the car battery, and the test results can be obtained easily and quickly after a period of time.