Use over regular sleepwear to take the place of loose blankets Unzips from the bottom for easy diaper changes. Generous sack design allows room for kicking, but cannot be kicked off so baby stays warm all night. Sleeveless design reduces the risk of overheating. Recognized as "Hip Healthy" by the International Hip Dysplasia Institute. "Back is Best" embroidery reminds caregivers to place baby on his or her back