Say Goodbye to Blisters: Balega Hidden Comfort socks are designed to keep your feet comfortable and ventilated, even during long distance runs. Ultimate Comfort: 84% Drynamix Polyester (Recycled) , 14% Nylon , 2% Elastane , these socks provide the perfect balance of comfort and support for your feet. Machine Wash. Hidden Comfort/Stretch. Extra deep heel pocket. Cushioning for impact resistance. Medium volume construction. New improved elastane throughout for a more structured fit. Seamless toe.