HALO Sleepsack M size *M size seems to be for 6-12 months. ~From the purchase site~ This is a swaddling sack for babies used in over 1000 hospitals in America to promote sleep. It's the perfect product for parents struggling with nighttime crying. Designed by an international research institute to promote healthy growth in babies. Made from high-quality materials, it's safe and secure for delicate babies. A very popular product overseas. Perfect for gifts. Used and washed. The feel and fluffiness are different from new. We inspect the item, but since it was worn by a child, there may be small scratches or stains. Please understand that this is a used item before purchasing.