Size: One size fits most; Foot to heel: Approx. 8.3 - 9.4 inches (21 - 24 cm); Heel to Opening: Approx. 18.9 - 20.1 inches (48 - 51 cm); 80 % cotton, 20 % polyurethane; Cotton blend, so it is very soft and comfortable. It is stretchy, very easy to wear.