High Quality: 64% Polypropylene, 27% Nylon, 7% Elastic, 2% Lycra Spandex Made in USA Small - fits Kids shoe size 12-5 Medium - fits Mens shoe size 6-9 or Womens 7-10 Large - fits Mens shoe size 9-12 or Womens 10-13 X-Large - fits Mens shoe size 12-15 or Womens 13+ Moisture Control, Odor Control, Antimicrobial, Breathable Mesh, Arch Compression, Blister Control, Ergonomic Cushioning, Heel & Toe Construction, Double welt top