1Function: Connect one end of the tester to the 13 hole plug of the trailer and the other end to the 13 hole socket of the car. The tester signal light will quickly show if the trailer or car coil is properly connected. 2Material: The tester is made of copper, nylon and PVC circuit board materials, with high temperature resistance, low temperature resistance and acid and alkali resistance, which can ensure long term stable test performance. 3Easy to Use: Simply connect it to the plug socket of the trailer or car, press the yellow button to test, and the LED light will quickly display the line status, convenient and quick. 4Wide Application: The tester is applicable for a variety of 13 pin plugs and sockets, and can be used for different types of vehicles such as motorhomes, trailers, and automobiles to meet diverse needs. 5Comprehensive Testing: The 13pin trailer plug tester quickly identifies issues with your trailer wiring, making it a critical tool for maintenance and safety.