Feature 1Smart Socket Tester: This socket tester can test every pin socket functions of the car, and the whole operation is very simple. 2Clear in Indication: There are clear lights and label on the test tool, this tester indicates quickly if a failure concerns the wiring. 3Wider Compatibility: One side can connect the 7 pins plug of a trailer and another side can connect the 7 pins socket of a car for test. 4Good ABS and Copper: Mainly made from premium ABS and copper material, not likely to malfunction and has good durability for long term use. 5Convenient Carrying: Comes with a compact size and a light weight as well, the trailer socket tester is very convenient to carry with you.Item Type: Trailer Socket TesterMaterial: ABS, copper. Battery Specification: 9V battery, not included. Applicable Range: Suitable for the test of N type 7 pin trailer plug socket connector. Trailers and RV can also be used. .wang-edit-text{ font-family:'Arial' !important; } .wang-edit-text table { border-top: 1px solid #000; border-left: 1px solid #000; } .wang-edit-text table td, .wang-edit-text table th { border-bottom: 1px solid #000; border-right: 1px solid #000; padding: 3px 5px; } .wang-edit-text table th { text-align: center; }Package List1 x Trailer Socket TesterNoteThe tester is not compatible with the LED light unit on the trailer.