Made of 100% Cotton. All three pieces in this set feature a Hello Kitty print: tank top, elastic waistband boxer, and elastic waistband pants. Great for lounging or sleeping! Machine wash cold. Turn inside out. Wash separately or with like colors. Gentle cycle. Only non-chlorine bleach when needed. Tumble dry low. Remove promptly. Cool iron if needed. Sizes run as follows: Sizes are as follows: Small (3-5), Medium (7), Large (9) and X-Large (11-13). This is the teen/adult line - the sizes run small, but this is not the kids line.