The Thorlos Skx Comfort Fit Socks were designed for feet that hurt. It provides a comfort fit for skiers on easy to varied terrains who wear rental boots to ensure maximum warmth, protection, comfort and best fit. This sock blends THOR-LON® and THOR-WICK&rg; to ensure maximum moisture transfer to keep your feet as warm and dry as possible. The Skx also has thick cushioning in the ball and heel for added warmth, protection, and comfort. The shin and instep are cushioned to protect against shin bite, and a ventilation panel ensures better air circulation.