Made with 75% Ultra-wicking Micro Denier Acrylic, 15% Nylon, and 10% Spandex for exceptional comfort and strength. ALL of our socks feature our "Stretch-to-Fit" sizing system and our exclusive "Easy-fit" cuff for a PERFECT FIT every time on any foot. We deliver Superior Quality and High-Tech Comfort in every SockGuy sock we make. Small/Medium fits a Women"s Shoe Size 6-10 and Men"s Shoe Size 5-9. Large/X-Large fits Women"s Shoe Size 10-14 and Men"s Shoe Size 9-13.