Basically, the length of the boards and the way they are made. The KC2 is 9 inch or 23 cm shorter than the other two. Therefore, it is more suitable for a smaller person or children on snow sailing. For ice sailing, all boards are equally enjoyable. The Snowfer KC 3X and KC4 EX are made from the same mould design. Both are top of the line boards but the KC4 EX has a higher impact resistance because its made of Epoxy V.E.R. resin that gives superior strength and lightness over regular polyester resin. Long boards are more enjoyable for snow sailing specially on deep snow. Starting in 2003 only the Snowfer KC5 Pro Race will be produce. The most upgrade of all Snowfer model.