A surcingle is a strap made of leather or leather-like synthetic materials such as nylon or neoprene, sometimes with elastic, that fastens around the horse's girth.
A surcingle may be used for ground training, some types of in-hand exhibition, and over a saddle or horse pack to stabilize the rider's weight. It also is a primary component of a horse harness.
A basic surcingle is unpadded, attaches around the horse by means of buckles or rings, and has no other hardware. A training surcingle, sometimes called a "roller," has many extra rings attached, running from the ribcage up to the withers area. It usually has padding to relieve pressure on the horse's spine. A variation of this design is used for equestrian vaulting.