Includes: Boot Covers with side zipper. Available in Child Sizes: Small (fits most toddler shoe sizes 6-10, up to 7" long), Medium (fits most youth shoe sizes 10-1, up to 9" long), and Large (fits most youth boys shoe sizes 2-7, up to 11" long). Boot Covers are intended to cover shoes measured from heel to toe of outside/bottom of shoe. This is an officially-licensed NASA costume accessory. This is an officially licensed NASA product.