Burton Ak Freebird Sock, True Black, Medium 44% Acrylic/30% Nylon/15% Polyester/7% Polyurethane/4% Wool Imported Medium-density cushioning throughout sock with elastic arch and ankle support and compression engineering to help muscles recover faster Chafe-Free Link toe system and stay high comfort band Ergonomic left and right motion fit with traditional Japanese Split toe tabi shape Figure eight construction improves ankle support and y-heel shape reduces heel lift Unisex sizing - made in Japan