72% Coolmax, 26% nylon, 2% spandex * Size small is thorlo sock size 9 which fits women"s shoe sizes 5-6.5- see size chart under images * Lightweight padding in arch and lace pad provides protection and better fit * Coolmax construction for moisture transport, excellent blister protection while keeping you comfortably cool * Wash and dry inside out (to fluff up the pads) using liquid fabric softener after each use (to lubricate the fibers for longer life). Liquid fabric softeners critical to receive full benefit of the product design