Use these warm-up booties during classes and rehearsals. They are perfect for dancers. Sizing: XS (US 13.5 - 1.5), S (US 4 - 6), M (US 6 - 8), L (US 8 - 10), XL (US 10 - 12). The booties have 100% Polyester filling for warmth, a cushioned heel, and a 100% Nylon Shell. There's a BLOCH rubber logo badge on the strap and they're not for outdoor use.