Quick Check --- This trailer hitch socket has one side for connecting a trailer's 7-pin socket and another side for connecting a car's 7-pin socket. This tester quickly indicates whether a fault is in the car's wiring or the trailer's wiring, effectively testing the problem of 7-pin plug and socket connection. European Universal Standard --- Passes Europe CE, ROHS Certification, ensures maximum strength and durability for long-lasting use. Such a practical trailer tester tool, you will need it. Reliable Quality --- The 7-pin trailer tester with safe and reliable performance, reasonable design. Dexterous appearance, practical use. The trailer tester socket is widely suitable for caravans, RVs, recreational vehicles, vehicles, trucks, trailers, etc. Tester requires a 9V battery (not included) High Performance --- The automotive trailer socket tester is made of high quality ABS and copper, frosted surface, durable and reliable, ensures maximum strength and durability for long-lasting