Good Luck Sock Men's Crew Socks - NASA Blue are 85% cotton, 10% polyester and 5% spandex. Fits shoe sizes US 7-12. Socks have reinforced heel & toe for better durability and just the right amount of stretch for all-day comfort. Machine wash cold (30 °C / 86 °F). Do not bleach or iron. Line drying will limit damage. Tumble drying may reduce lifespan.