Heavy weight OTC performance. Designed to provide exceptional softness, durability, and climate control. The natural qualities of wool substantially improve wicking action and moisture management, keeping feet drier and more comfortable. Over the calf construction and padded protection for heavy hiking and the coldest outings. 75% Merino Wool, 15% nylon, 10% Lycra. Mens shoe sizes: M: (7.5-9.5), L: (10-12.5), XL(13-15).