Fight the funk! The Cupron® material built into these socks makes the most of copper’s natural antimicrobial properties. Cupron® is EPA approved to kill 99.9% of bacteria. Made with moisture wicking TransDry® cotton to keep feet cool and dry with a Cupron® copper heel and toe. Both the OTC and Crew Socks feature compression zones designed for fit and all-day comfort. They’re more than socks, they’re foot armor. 82% polyester, 16% Cupron® copper yarn, 2% spandex.