1. Application and technical data: The trailer tester is largely suitable for 12V wagons, motorhomes, leisure vehicles, trucks, trailers, etc. With LED indicators, it can display errors in the wiring circuits of the vehicle or trailer. 2. Application: This 7pin trailer socket plug tester (lighting diagnostic device) can be used for trailers, caravans, etc. (only for European vehicles). It serves as a good replacement, directly replacing old or broken ones. 3. ABS brass: The trailer plug tester is made of quality ABS plastic and brass. ABS features pressure resistance and corrosion resistance. Professionally crafted, it is lightweight, durable, and has a long service life. 4. Compatibility: This trailer socket tester is suitable for 7pin plugs and sockets, including 13pin plugs and sockets. It is a 12V plug for electric trailer plugs and sockets, ensuring safe and reliable performance.