Features 1.Widely Used: Trailer towing lights wiring circuit tester is compatibale with trailers, caravans, horseboxes, bicycle, carriers, etc. Meeting different demands. 2.Simple Operation: One side connects to the plug of a trailer and the other side to the socket of the towing vehicle, effectively test what the problem is for plug and socket connection. 3.Powerful Function: Our tester is designed to fastly and quickly search for cable line defects on trailers and on towing vehicles. Indicating any failures in the wiring circuits on the car or trailer. 4.Reliable and Practical: With safe and dependable performance, reasonable design, deft appearance, convenient usage. Reliable quality and delicate workmanship. 5.Full Set: Including a trailer tester, a plug and a socket of the package, providing reliable solution to your trouble and ensuring maximum strength and durability for long lasting usage. Specification Item Type:TrailerWiringCircuitTesterColor: BlackMaterial: ABS+CopperBattery: 9v(Not Included)Application: Package List 1 x Tester1 x 7 Pins Socket1 x 7 Pins Plug