NCAA Cycling/Running Socks nylon Original airflow design sock and the first sock with a wide-open mesh-weave foot top, 60% Nylon, 39% CoolMax EcoMade, 1% Lycra Top cuff is knit with Lycra Nylon to eliminate sagging. Reinforced heel & toe extends life in high abrasion areas and toe seam is low bulk and extremely strong. Nylop plated to outside of foot sole for lasting durability. CoolMax EcoMade plated to inside of foot for maximum moisture transport and AirEator mesh weave instep is lightweight and speeds drying.