The HO Coefficient X features a traditional polyurethane foam core that keeps you in balance and on edge. Designed to be forgiving, it will give you an easier ride in less than perfect conditions. The revolutionary step concave base design gives the ski more lift and less drag. Across the wake, the Coefficient X will carry more speed and give you time for your next turn or buoy. A blend of carbon fiber/fiberglass reinforcements reduces torsional flexing. 5-stage rockerline. Animal binding sizes: S(6-7), M(8-9), L(10-11), XL(12-13).