The sock within a sock. The inner layer stays with the foot, the outer layer moves with the shoe. Tactel inner wicks perspiration to absorbing outer layer, keeping feet cool and dry. Total comfort, no blisters, and no wear-out.
Walking socks are a wool / nylon outer with tactel inner.

Size guide:
Small: 3 - 5.5
Medium: 6 - 8.5
Large: 9 - 11.5
XLarge: 12 - 14