This addition to our incredibly popular line of bamboo socks, the Performance Sock, has an added arch support weave as well as a new heel cup weave to help maintain sock alignment with the contours of your foot. The basic fabric of the sock is still the time tested half-cushion design, featuring a moderate pad to cushion the sole from impact while the top flat weave provides increased ventilation. For added style, our sock features a grey-natural color scheme and a woven "Spun Bamboo" at the edge. Give these a try and, like all our Spun Bamboo products, if they are not a significant improvement over what you have been wearing, you may return for a complete refund. 87% viscose from Bamboo/10% Nylon/3% Spandex. Designed in California, made in China.