DRYSTAT infused with silver for a natural bacteria resistant, wicking and quick drying material. - SIZE CHART: Small (Women's 5-8, Men's 4-7), Medium (Women's 8-10, Men's 7-9), Large (Women's 10-12, Men's 9-11), X-Large (Men's 11-14). Due to the stretchability of the sock, if your shoe size is between sizes, choose the smaller. - FUNCTION arch and gentle plantar ligament support, part of your long term foot care - PREWASHED using a "chemical free" softener, each sock is inspected by hand for quality and function. - QUALITY Every product is made to strict specifications in our Italy factory never outsourced to the lowest bidder.