Pro Choice Comfort-Fit SMx H.D. Air Ride Western Pad - Diamond Bar, Developed from the horse’s back up, the Comfort-Fit SMx Air Ride Saddle Pad is contoured to follow the curve of the horse’s spine. As a result, the pad locks in place on the horse’s back, allowing full movement. The SMx Air Ride™ core is made of a unique material found in the protective gear of professional human athletes for absorbing shock while allowing air flow to the skin, the SMx Air Ride core’s natural cooling system lowers the horse’s body temperature and slows the rate of fatigue.