Description of Nordica Spark Ski Boots Designed by Nordica’s freeski athletes and engineered for the aggressive skier looking to spark their progression in the park, pipe, and beyond the Spark freeski ski boots Twin Energy driver, tried and true comfort, and superb suspension technology brings you a bomb proof freeski boot for the entire mountain. Spark it up! Features: Sizes:23.0-30.5 MP Shell and cuff material:Polyether-SOFT Liner:Comfort Fit FSE Footbed:Comfort Fit Flex index:80/70 Buckles:4 Micro Alu + 2 Servolock on cuff Velcro strap:ENERGY DRIVER (by BOOSTER®), 35 mm Wedge:Full Shock Eraser Rear spoiler:Height Adjustable