Quick Check - This trailer tester is designed to test 7 pin plugs and sockets on car and trailer. This tester quickly indicates whether a fault is in car wiring or trailer wiring, which can effectively test the problem of 7-pin plug and socket connection. European Universal Standard - Pass Europe CE , ROHS Certification, universal 7 pin trailer tester For European vehicles, the 7 pin tester can effectively test the problem of lighting connections. Reliable Quality - The 7 pin trailer tester with safe performance and reliable, reasonable design. Skillful appearance, convenient use. Easy to store Can be used with trailers, RV, caravans, bike racks, Testing requires 9V battery (not included) Easy to Assemble - Made of high quality ABS and copper material, frosted surface, durable and reliable, ensures maximum strength and durability for long lasting use, One side connects to 7 pin plug and the other side to 7 pin socket, also can be applied to 13 pin with the adapter. Confident Product - Product listed by , friendly customer service. But if for any reason you are not completely satisfied with the product, we will refund your money. Well let you know, well be happy to help