The Core NXT Sock features include lightweight, blister prevention, reinforced heel and toe, breathable mesh instep, elasticized instep, and seamless underside toe closure. The materials used in this sock are OUTER: 42% Stretch Nylon, 37% X2O® Acrylic, 12% Polyester, 7% Spandex, 2% Tencel® LINER: 100% Olefin.