Heavyweight Columbia Blue, Medium Solid Color Tube-sock 80% hi-bulk acrylic / 20% stetch nylon Thick with hi-bulk acrylic and stretch nylon for hard-pounding athletes 18 athletic colors to match any uniform Longer design for turn-down cuff or to cover the knee This style fits Medium sock size 8.5 to 11. Look for all fours sizes: 780-adult, 770-medium, 760-small and 750-child.