Designed for the coldest climbing conditions, the Koflach Men's Arctis Expe mountaineering boots are particularly suitable for high altitudes, low temperatures, and long expeditions. . Y Technology combines rigid plastic for support and secure crampon attachment with supple plastic for ease of lacing and natural walking comfort. Vario cuff articulation allows natural side to side and and fore aft flex for a bit of leather boot performance. Vibram Dhaulagiri sole is optimal for high alpine expeditions, blending climbing 'zones,' push and brake 'zones,' and stability 'zones' for true all mountain function. Steel roller lacing provides unparalleled tightening without unnecessary exertion. Rubber randing absorbs impact and improves climb ability. Pebax plastic is lightweight and strong in any temperature. Removable Arctis Expe High Altitude liner boots provide comfort and warmth with 7 mm lightweight EVA and a reflective coating for added heat. Note: These boots are UK sized and shipped according to their UK size. Please use the size chart to find your appropriate UK size.