Sockguy 3'' Performance Socks Stay Strong - S/M 75% Ultra-wicking M.D. Acrilyc, 15% Nylon, 10% Spandex Double stitched heel and toe Stretch to Fit Sizing System for Perfect Fit S/M Fits Mens Shoe Size 5-9 and Womens Shoe Size 6-10. L/XL Fits Mens Shoe Size 9-13 and Womens Shoe Size 10-14. Made in the USA