Darn Tough Men's Wool Mountaineering Extra Cushion Socks, 6 Pack 24% nylon PAY FOR 5 AND GET THE 6th FOR FREE 73% Merino Wool 25% Nylon 2% Lycra Spandex Made in the USA, Unconditional Lifetime Guarantee Performance fit and Unsurpassed durability Men's Sizes: Small 5.5-7.5, Medium 8-9.5, Large 10-12, X-Large 12.5-14.5, XX-Large 15-17