Patented Body Geometry design is lab tested to assure blood flow to sensitive arteries. Stiff, carbon-reinforced shell tuned for ride compliance. Tuned-density PU foam padding is lightweight and supportive. Ultra-light and strong oversized FACT carbon rails. Tough, light and water resistant Micromatrix cover. NOTE: Oversized 7x9mm carbon rails are not compatible with seatposts equipped with side-load clamp mechanisms for 7mm round rails.