The StringKing athletic low cut socks are made with performance fibers called TENCEL which reduces odors and provides thermal warmth. These socks securely fit to your foot at al times. The mesh construction across the toes keeps your feet from overheating. Sizing: Small - Men 3 - 6 & Women 5 - 8 Medium - Men 6 - 9 & Women 8 - 11 Large - Men 9 - 13 & Women 11 - 15