Connelly incorporated everything they know about skiing into the Sonic slalom ski. The sidecut is wide in the tip and narrow in the tail. Hook grooves on each side of the tunnel, 6 V-shaped steps, for a more efficient, faster feel on the water and the most forgiving flex pattern ever created. Together this makes the Sonic ski extremely easy and fun for skiers carving up the lake. The Connelly Sonic features CAPT construction with closed cell polyurethane resin core. Hand-tuned Acrylam base. Aluminum drop-through fin with foil. The Sidewinder brings Hinge Tech to the masses with the first and only step-in waterski binding at a value price. Pull the lever down, and step into the binding effortlessly. Pull the lever up, and feel the zero heel lift. Lycra lined heel and toe hold your foot snug and secure. Sidewinder Boot sizes: S(5-7), M(8-9), L(10-11).