The DeFeet «Flying D» logo on these socks is the badge worn by all of our top athletes. This model carries the 5″ DOUBLE CUFF which creates a slightly thicker, burlier and even more durable arrangement. The Aireator is the airflow design sock that changed how modern endurance socks are made. With its trademark venting mesh weave foot, durable StayFast cuff and plated heel & toe that wear like iron, the Aireator guarantees long-lasting performance. Made with CoolMax® EcoMade™, the fiber that is made from recycled resources.