U.S. Marines, USMC, Coolmax Cycling and Running Socks United States Marines Officially Licenced Socks Advanced Air Transfer System - - 50% Acrylic, 25% Nylon, 15% Spandex and 10% Lycra Dries 75% faster than a cotton sock, keeping your feet drier and cooler in all weather conditions An Easy Fit non-binding double cuff with exclusive comfort support and to ensure a great fit on any foot Cool airflow mesh above your foot allows for maximum ventilation and breath-ability