The Alpina Alaska BC nordic boots have a full grain upper that combines rigidity and durability yet flexes comfortably. The Thinsulate insulation keeps feet warm for all-day tours. It is hard to find a better NNN-BC boot for out-of-track touring. Full grain leather upper ThinsulateA(R) liner Speed lacing system Soft collar Anatomic footbed Toe box protection Medium boot flex Alpina Size Chart EU Sizing US Women&';s US Men&';s 36 5 4