Competitive and recreational runners alike will be impressed by the PhD Running Ultra Light Micro sock from SmartWool. Itchless and odor-free, these ultra-light running socks offer excellent natural fiber performance. These non-cushioned socks are designed to keep you cool as the temperature rises during long runs. Padded Achilles tab for protection and secure fit. High-density impact zones for shock and abrasion. Mesh zones for added ventilation. Micro height. Smartfit II 4-point banded fit system. SmartWool inside for temperature, moisture, and odor control. Fabric: 60% wool, 38% nylon, 1% spandex, 1% other. Package of three pairs of socks.