This trailer tester helps quickly check circuit failures in vehicles and the 12V electrical system on trailers. Simply insert the lighting and cable tester into the socket or plug to be tested; press the test button and receive a clear diagnosis via the LED display. It is easy to use and practical. The 12V tester connects to the trailer's 7-pin plug on one end and the vehicle's 7-pin socket on the other. The tester's signal lights quickly indicate whether the trailer or vehicle wiring is properly connected. Designed for 7-pin connectors. Identifies faults in the vehicle or trailer circuit. Portable, compact, and hand-held for easy storage. Ideal for commercial and private use, including workshops, car and trailer rentals, and accessory retail. Adapter: 7-pin Voltage: 12V Size: 19.7 x 5.3 x 4.3 cm Material: ABS + copper Color: Black Package Contents: 1 x Trailer Tester 2 x Adapter Note: Light and display differences may cause slight color variation between the image and the actual item. Measurement error allowance is +/- 1-3 cm.