Thorlo's Crew Length Light Hiking Sock Is Designed For Day Hikes in Moderate To Hot Weather On Flat or Varied Terrain. Light Weight Padding in The Ball Of the Foot and The Heel Helps To Protect Against Painful Blisters and Impact. Light Padding Across The Top of The Foot Protects Against Boot Lace Pressure While Spandex and Low Density Padding In the Arch Creates A Snug Fit. A Special Blend Of 62% Coolmax®, 19% THOR-LON® Acryllic, 13% Stretch Nylon & 4% Spandex Fibers Promotes Moisture Wicking For Cool Comfort On Those Long Hot Walks. (Sock Size 9 = Womens Shoe Size 5-6.5, Sock Size 10 = Womens Shoe Size 7-9, Sock Size 10 = Womens Shoe Size 9.5-11.5.)