Swiftwick Aspire Four Socks With managed compression, the Swiftwick Aspire Four socks have proven to reduce swelling, improve circulation and increase your endurance. They are crafted on a 200 needle machine for unrivaled comfort and fit. Moisture management wicks sweat away without the use of chemicals for a completely fresh and dry experience. The cool, striped design works well with the trendy crew length cut. Linked, seam-free toe. Sculpted footbed and seamless toe assures maximum comfort and a blister-free environment. A lighter, thinner T-66 nylon Olefin material at the toe, heel, and footbed for optimal airflow and targeted compression. A half-density weave allows for a streamlined fit without bunching of fabric. Includes Swiftwicks Signature Double Welt Compression Cuff that wont fall down during movement. Thin channeled upper material for breathability. Made in USA.The only Nobel Prize winning fiber, these socks are constructed with 46% Olefin which retains less than .01% of its weight in moisture and resists deterioration from perspiration and detergents. Sizing Small: Men's 3-5½ / Women's 5-7½Medium: Men's 6-9½ / Women's 8-10Large: Men's 10-13 / Women's 10½-14Extra Large: Men's 13½-16 / Women's 14½-16½U.S. shoe size equivalent.