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