1000 Mile Lightweight Walking Sock - SS19 Tactel inner layer - Wicks moisture to keep you dry and comfortable. Soft merino wool-mix outer layer - Moves with the shoe while the inner layer moves with the foot, to prevent blisters and reduce wear. Arch bracing - For additional support. HeelPower design - Grips the heel firmly in place to reduce slippage. Fabric - Outer layer: 63% merino wool, 34% nylon, 3% Lycra. Inner layer: 100% Tactel.