The 7 pin trailer socket is a replacement socket for caravans and trailers. This tool allow trailer board lights to mimic the towing vehicle.
? Body style: plastic
? Standard 7-Pin Connection
? Pin style: Brass pins with screw terminals
? Compliance standards: ISO1724
Material: shell (nylon), needle (58 copper), tail (PVC plastic cover) , screw (iron plating)
Executive standard: ISO 1724
Voltage: 12V
Dimensions in millimeters
http://www.willingcorp.com/auto-tools/trailer-socket/7-pin-trailer-socket.html