Medium, Gray, Boot Sock, A Technically Advanced Sock Featuring Outlast Adaptive Comfort Fibers, Outlast Balances Temperature So That Your Feet Can Stay Dry & Comfortable Throughout The Day, 40% Outlast Acrylic, 23% Olefin, 18% Stretch Nylon, 17% Wool, 1% Spandex, 1% Stretch Polyester.