Thorlo's Crew Length Sock is The Ultimate in Protection for Every Day, All Day Walking. Midweight Padding at the Ball of the Foot and Heel Protects Against Shock and Shear. Patented THOR-LON® Fibers Throughout the Body of The Sock Wicks Moisture Away, Reducing Blisters and Keeping Feet Drier. Lightweight Lace Padding with Spandex Across the Top of the Foot and At the Arch Provide a More Comfortable and Supportive Fit. 82% THOR-LON®, 13% Stretch Nylon, 5% Spandex. (Sock Size 13 = Mens Shoe Size 13-15.)