Hopkins Manufacturing Corporation makes your towing experience simpler and more rewarding through innovation and value. Hopkins offers a variety of towing solutions including vehicle wiring kits, adapters, vehicle and trailer connectors, breakaway systems and much more. Today, more than 40 percentage of retail category sales are generated from Hopkins innovations. Six pole rounds provide two additional functions not found in 4 poles. These functions are electric brakes and an auxiliary power lead. The most common use for this type of plug is for horse trailers.