SkiTrax(TM) ski boot traction devices have a unique patent pending "Roll Sole" design that promotes a natural walking motion. SkiTrax will protect ski boot soles from excessive wear ensuring a proper fit in ski bindings. Features: Stretch/ durable rubber Raised rubber traction bump sole Size Small: Mondo sizes 24 - 27 Size Medium: Mondo sizes 27.5 - 29.5 Size Large: Mondo sizes 30 - 31.5