Balega socks are engineered with the company's proprietary DryNamix moisture management technology that keeps feet cool and dry while allowing free airflow for maximum comfort, performance and durability. All of Balega's running socks have been race tested and incorporate a hand linked seamless toe, eliminating abrasion across the top of the foot. The company also knits an extra deep heel pocket ensuring that each sock fits the foot perfectly and does not slide down during a run. VTech Arch Support System for adds structure along the arch of your foot, and extra cushioning on the heel for impact resistance. Designed with a medium volume construction. Drynamix Polyester 79%/Nylon 19%/Elastane 2%.