Sleeveless design prevents overheating and rebreathing. Inverted zipper for easy diaper changing. 100% polyester. "Back is Best" logo reminds caregivers to put baby to sleep on back. Recommended by CFSIDS Eliminate loose blankets from baby's crib by zipping them into the Halo SleepSack, the original wearable blanket. The sleeveless design prevents overheating and reversible zipper is made for easy diaper changes. Baby stays covered all night long, safely and comfortably in 100% polyester. Expanded assortment available online. This product is not available in our stores.