The HALO SleepSack Swaddle replaces loose blankets in the crib that can cover your babys face and interfere with breathing. In addition to helping your baby sleep safer, it helps him sleep better, too. Its adjustable swaddle wrap immobilizes your baby's arms to prevent the "Moro" or startle reflex. And, it is the only 3-way adjustable swaddle that adjusts to your babys sleep style. Swaddle arms in, hands-to-face, one or both arms out to ensure babys best sleep and an easy and gentle transition to the SleepSack wearable blanket when it is time to stop swaddling. Used in hospitals nationwide, the Halo SleepSack Swaddle is the #1 choice of hospitals and is recognized as "Hip Healthy" by the International Hip Dysplasia Institute. Its strong adjustable fasteners ensure a perfect fit and resist breakouts for more secure swaddling. Plus, its innovative zipper, unzips from the bottom allowing your baby to stay swaddled for easy diaper changes. HALO also proudly supports non-profit organizations like First Candle/SIDS Alliance. Use over regular sleepwear to take the place of loose blankets. Discontinue swaddling when the baby shows signs of rolling over or breaking out of the swaddle wrap. 100% polyester micro fleece. TOG: 3.0 Size preemie fits birth 5lbs, size newborn fits 6-12 lbs, size small fits 13-18 lbs.