Main Material --- ABS and Copper Quick Check --- This trailer hook socket has one side for connecting the 7-pin socket of a trailer and another side for connecting the 7-pin socket of a car. This tester quickly indicates whether a fault is with the car wiring or the trailer 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