Size Chart Description 65% Polypropylene/12% Spandex/8% StaCool®/6% Nylon/6% Endurall® wicking yarn Polypropylene yarns for superior moisture wicking and to provide bacteria/odor resistance StaCool® nylon for added moisture wicking capabilities and strength Endurall® knit-in heel and toe for abrasion resistance Left/right technology provides strategic anti-abrasion zones Arch support for better fit and increased circulation Half-cushion foot for shock absorbency and breathability Size Chart Small: If your Shoe Size is Childrens 12 1/2 to 7: Womens 4 to 5 1/2 then your Sock Size is 7-9 Medium: If your Shoe Size is Mens 4 to 6: Womens 5 1/2 to 10 1/2 then your sock size is 9-11 Large: If your Shoe Size is: Mens 7 to 13 then your sock size is 10-13 Extra Large: If your Shoe Size is Mens 14 and Up then your sock size is 13-16