Usage Tips:[QUICK TESTING]7 pin trailer plug tester integrates 7 signals from your truck, ensures quick 30-second check including tail marker (TM), brake (BK), backup (BU), left turn (LT), right turn (RT), stop (LT+RT), and 12 volt auxiliary power [PLUG & PLAY]This trailer wiring tester is equipped with a standard 7 way connector, easy to install, ideal for trailer, RV, truck, pickup, camper, and other towed vehicles [180° ROTATABLE HEAD]Our 7 round pin trailer light tester head is 180° rotatable-just loosen the screw and rotate the tester head as you want; Whether you have an upward or downward trailer socket, the tester indicator is available [PREMIUM MATERIAL]This 7-pin tester is built with 99% pure copper pins and sturdy plastic housing, providing better conductivity, more reliable performance and longer lifespan for your truck [COMPACT SIZE]The compact 7 way tester is easy to store in your glove compartment, toolbox, cab organizer, under-seat storage or trailer storage compartment, allowing you to test trailer wire no matter at home or on the road Colour:Black Material:plastic Package Contents: 1 x Trailer Plug Tester Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.