The O'Brien Siege is a streamlined ski that's designed to deliver speed and stability. This is the same shape found on the popular O'Brien Sixam 2.0. With a tunnel concave, edge changes are effortless and the ski turns on a dime. A softer flex and increased rocker make the Siege feel stable right out of the box. Small defined bevels mean faster, easier turns. ARC fin. X-9 Adjustable Plate Binding has a front lace system for easy entry and exit and built-in lateral stiffeners. X-9 Binding sizes: XS/S(up to 7), STD(7-11), 2XL(12+). Pro Wing foil not included.