A harness is a device by which a horse or other animal is attached to the load it is pulling. Harnesses usually consist of a bridle, a collar or breastband, a backhand, a bellyband, a crupper, and reins.
The bridle, which is worn on the horse's head, keeps the bit in the horse's mouth. The collar is a heavy padded leather ring that fits around the base of the draft horse's neck.
A horse pulling a light load usually wears a leather band called a breastband instead of a collar. The backband is held in place by another band that encircles the horse's belly. A backband is used when one or more horses draw a load between shafts or alongside a pole.
The crupper, or loop under the horse's tail, helps to keep the harness in place.