FITS Ultra Heavy Expedition Rugged Boot Sock - Men's Heavyweight full foot cushioning for warmth and protection - heaviest sock available in the FITS line Color-Replacementd seam on toe so you won't forget your size Made in the USA Materials: 74% Wool, 13% Nylon, 3% Polyester, 8% Acrylic, 2% Lycra Spandex Sizing: Small: Men's 3.5-5.5, Women's 5-7. Medium: Men's 6-8, Women's 7.5-9.5. Large: Men's 8.5-10, Women's 10-11.5. X-Large: Men's 10.5-12.5, Women's 12-14. XX-Large: Men's 13-15.5, Women's 14.5-16.5.