The SleepSack® wearable blanket replaces loose blankets in the crib that can cover baby's face and interfere with breathing. In addition to sleeping safer, the SleepSack® wearable blanket helps babies sleep better, too. It's a warm cuddly blanket they can't kick off; ensuring baby sleeps soundly throughout the night. Unzips from the bottom for easy diaper changes. Made of super-soft, micro-fleece, offers superior breathability, making it perfect for year round use. Machine wash with like colors. 100% polyester. Size small is for babies up to 6 months (10 - 18 lbs.), medium is for babies 6 to 12 months (16 - 24 lbs.), and size large is for babies 12 to 18 months (22 - 28 lbs.). Specify color and size.