A fifth wheel is a form of travel trailer designed to be towed by a pickup truck. A coupling pin connects to a round horizontal plate (the "fifth" wheel) mounted on the bed of the truck. Fifth wheels are easier to tow than travel trailers because part of the load is placed over the towing vehicle rather than behind it. By extending part of the front box over the truck bed, a fifth wheel can be up to six feet shorter than a travel trailer of similar size.