1000 Mile Fusion Anklet Running Socks Full padded achiles tendon protection - helps to the sock a real cushioned feel and helps to prevent injury. Arch bracing - helps to give additional support. Double layer construction - eliminates friction betweenthe foot and the shoe, reducing wear and preventing blisters. Tactel inner layer - wicks away perspiration to keep the feet dry and cool Outer Layer - 57% Nylon, 41% Tactel, 2% Spandex