Utility trailers are flatbed trailers designed to haul equipment. They can vary from small units for hauling equipment such as motorcycles to large, heavy-duty units for hauling tractors, implements, and supplies. Trailer tongues attach to the rear of a truck with a ball or “pintle” hitch or a “gooseneck” hitch that attaches to a pin (fifth-wheel or king-pin) in the truck bed. Bed length varies from 6 to 40 feet. They may use 1, 2, or 3 axles with single or dual tires. Some trailers are equipped with manual ramps to facilitate loading tractors. Loading ramps are usually steep and tractors must be loaded carefully. In some cases, when implements are attached to the tractor the steep angle stalls the loading operation. Tilt-bed trailers, some equipped with a winch, are available to facilitate loading. These small to medium size utility trailers can range up to about 40,000 pounds carrying capacity. Licensing agencies may rate trailer by GVWR (gross vehicle weight rating) or GAWR (gross axle weight rating). Larger trailers are classified as semi-trailers, and they may reach up to 100,000 pounds capacity or more.