Size Guide:S: US Men 5-8 US Women 6.5-9.5, UK 5-6.5, EU 37-40M: US Men 8-11, US Women 9.5-12.5, UK 7-9.5, EU 40.5-44L: US Men 11-13, US Women 12.5-14.5, UK 10-12, EU 44.5-47 XL: US Men 13.5-14.5, US Women 14-5-15.5, UK 12.5-14, EU 47.5-48.5 *(if you are in between sizes, we recommend sizing up) Tight restrictive socks compress the foot into an unnatural shape which can affect how you walk, run and move. Whereas the All Day Stride Toe Socks allow the toes to splay to provide a stronger and more natural foundation. The anti-slip grip is designed to give you more traction during your workout. Individual toe compartments allow your toes to splay so you can easily grip the ground and generate more power in your training. Material 75% combed cotton, 20% nylon, 5% spandex Returns and Exchanges For health and hygiene reasons some products are not able to be returned for incorrect sizing or change of mind. This includes Toe Spacers, Rock Mat, Toe Socks, and Grip Socks.