Brooks Versatile Double Tab Sock, 3-Pair Pack Dri-Stitch Nylon 96% Dri-Stirch Nylon, 4% Lycra Arch compression helps prevent socks from sliding into the shoe during physical activity. Y Heel gore creates a deeper heel pocket, providing a better fit. A flat under toe seam all but eliminates the chance of blisters caused by friction between harsh seams and toes Machine Washable, Tumble Dry on Low, non-chlorine bleach as needed USA