Alpina Sports 2013/14 RSK Cross-Country Nordic Skate Boots Stiff NNN R3 Racing PU sole designed for skating Plastic heel counter with heel-grip system, cuff and power strap provides heel hold-down for close ski contact, power transfer and edge control Elite lacing system, power strap and anatomic footbed ensure a secure fit for performance skiing Thinsulate insulated waterproof uppers with elastic calf adjustment and waterproof zipper closure ensure your feet stay cozzy Designed for use with NNNR3 Skate and Xcelerator bindings