Trailer tester can help you quickly check the circuit failure of both vehicles and 12V electrical system on trailers. Simply insert the light and cable tester into the socket or plug to be tested, press the test button, and make a clear diagnosis via the LED display. It is easy to use and convenient. The 12V tester is connected to the 7-hole trailer plug at one end and the 7-hole car socket at the other. The tester's indicator light will quickly indicate whether the trailer or car coil is properly connected. Suitable for 7-pin connectors. Indicates faults in the vehicle or trailer circuit. Portable, easy to store and carry. Perfect for commercial and private use, workshops, car and trailer rental, accessories, etc. Adapter: 7-pin Voltage: 12V Size: 19.7x5.3x4.3cm Material: ABS + copper Color: Black Package Contents: 1 x Trailer Tester 2 x Adapter Only the above package content, other products are not included. Note: Light shooting and different displays may cause the color of the item