Wigwam Merino Comfort Hiker 2 Pack Cushiony all overSmall fits Women's shoe size 4-7 Foot hugging fitMedium fits Men's shoe size 5-9.5 and Women's shoe size 6-10 Stay up leg and topLarge fits Men's shoe size 9-12 and Women's shoe size 10-13 Seamless toe closureXlarge fits Men's shoe size 12-15 67% Merino Wool, 21% Stretch Nylon, 7% Elastic (rubber), 5% Acrylic