This crew sock keeps you comfortable throughout the day with extra durability added to high-impact areas, more than enough stretch, and improved ventilation. . . . Made out of a combination of 63% merino wool/35% nylon/2% elastane. . Strategically placed mesh improves ventilation for temperature and moisture management. . Virtually Seamless??? flat knit durable toe seam. . 8.5 in. tall. . PhD?? performance adds two elastics for better recovery and more stretch. . 4 Degree Elite Fit System combines two elastics for better recovery and stretch. . Indestructawool??? uses a patent-pending construction to elevate durability and comfort. . Medium cushioning for impact absorption. . Made in USA. . 888658520053 29103600015 SW001071