Swiftwick socks provide your feet's 60 joints, 200 ligaments and 35 muscles with the support of engineered performance in mechanical construction, fiber and compression technologies. From the Y-heel design to the chassis -- a thin, channeled upper -- with "no seam" design, each Swiftwick sock is constructed for optimum breath-ability, durability, comfort and support. Made in the USA with a culture that promotes manufacturing the very best socks through environmentally friendly means and socially responsible practices.