65% Merino Wool, 31% Nylon, 4% Lycra® Spandex; Machine wash in warm water on gentle cycle with socks turned inside out. Do not bleach. Tumble dry on low. Do not dry clean. * Custom shrink treated Merino wool holds its shape and wont shrink * Reinforced heel and toe for a very long lasting sock * Elastic arch support helps provide endurance for your feet * United States