Zero Cold Weather Crew SockLayering Position next to skin Product Features Sizing: Size 10 and under should order Size SM MD. Sizes 10 and up should order Size LG XL Wool blend offers warm, odor resistant comfort whether dry or wet High loft, insulating knit for cold weather Flat knit toe seam prevents chafing and hot spots Crew length fit extends to base of calf Increased durability in high abrasion areas Materials 68% merino, 30% nylon, 2% spandex