The SwaddleDesigns Transitional Swaddle Sack is designed for babies who prefer to sleep with their arms up, are starting to roll over, or can break out of a traditional swaddle. It features half-length sleeves with mitten cuffs that can be worn open or closed, allowing the baby to self-soothe or be protected from facial scratches. The snug fit around the tummy and shorter sack support the baby's legs in a flexed position, promoting better and safer sleep. Made from soft, stretchy cotton knit, it includes a helpful 2-way zipper for easy diaper changes.