Before 1988, the only trailer connector in common use was a 6 pin unit (There were some 5 pin plug/sockets found in Victoria, TAS, SA NT). Since 1988 you must have a 7 pin (minimum) connector in order to register your boat, camper trailer etc. (You may need a bigger connector in some cases, so consult an auto electrician for this). All trailer plugs and adaptors are made from the highest quality material. A range of the most common 7 pin trailer plugs and sockets, featuring easy to use screw down terminals, corrosion resistant metal contacts and high quality UV stabilised plastics. In each type, the socket is fitted to the vehicle, and the plug is fitted to the trailer. Often we find that the trailer we've borrowed from a mate does not plug into the socket on your vehicle, and that's where these trailer plug adaptor leads come in handy. About 20cm in length, and 6 versions available to fix up any mismatch of the 7 Pin Flat, 7 Pin Large round and 7 Pin Small round trailer Input Type : 7 Pin Flat Trailer Input Connection : Plug Output Type : 7 Pin Round Trailer (Large) Output Connection : Socket Output Quantity : 1pc