it has panels: these are a pair of pads attached to the underside of the seat and filled with wool, foam, or air. Although some modern saddlers have developed alternative models, the English saddle is usually constructed on a framework known as a tree. The tree is made of wood, spring steel, or composite, and it supports the rider on a sling of webbing between the firm pommel (front of the saddle) and cantle (back of the saddle). On either side of the tree, a steel hook known as the "stirrup bar" is affixed. It is upon this hook that the rider hangs the stirrup leather, which is a very strong leather or nylon loop supporting the stirrup. More very strong leather or nylon straps known as billets (or girth points/straps - UK) are attached to stout webbing which is tacked across the top of the tree, to which will eventually buckle the girth--the beltlike strap which holds the saddle onto the horse. The tree and its various parts are upholstered with a covering made of leather, nylon or microfiber and shaped to form the seat above and the panels below. In addition to the seat and panels, English saddles feature leather flaps on either side; the underside flap is called the sweat flap, and the upper flap is called the saddle flap (or, simply and appropriately, the "flap"). The flaps sit between the rider's leg and the horse's side and protects the horse from being pinched by the stirrup leather or girth, and the rider's leg from being chafed by the girth buckles. On some saddles it is also specially padded to protect or support the rider's knee. Styles of English saddles The differences between the styles of English saddle are small but significant. The most important distinctions are the location and therefore the balance of the seat, and the flap length and shape. A saddle used for a discipline where the rider sits more upright with a longer leg, such as in dressage, has a flap that is longer to accommodate the leg, and less inclined forward (as the knee does not need to go forward). The seat will also be closer to the withers, to keep the rider's center of gravity in the correct spot. However, in disciplines where the rider needs shorter stirrups for better balance and security, such as in the jumping disciplines, the saddle