Brooks Versatile No Show Sock, 3-Pair Pack Dri-Stitch Polyester 68% Dri-Stitch Polyester, 29% Nylon, 3% Lycra Y Heel gore creates a deeper heel pocket, providing a better fit. A flat toe seam all but eliminates the chance of blisters caused by friction between harsh seams and toes Y Heel gore creates a deeper heel pocket, providing a better fit. A flat 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