The Transitional Swaddle Sack is the easiest & safest way to transition baby from a traditional swaddle. The arms up sleeve design allows baby to self-soothe and the unique -length sleeves with foldover mitten cuffs closed provide partial suppression of the Startle Reflex to promote better sleep; and, if baby rolls over during sleep, the sleeves allow baby to use arms to lift torso and head to access air to promote safer sleep. The Transitional Swaddle Sack is ideal for babies who prefer to sleep with arms up, babies who are starting to rollover, and babies who break out of a traditional swaddle. The uniquely-shaped, -length sleeves are not full length, so when mitten cuffs are closed, babys arms will be flexed close to body for swaddle snugness. The foldover mitten cuffs may be worn open or closed. Caregiver can open one or both cuffs, so baby can self-soothe by sucking directly on hand. Helpful 2-way zipper with 2 zipper pulls. The zipper zips down from the top to make it easy to place baby in the sack and zips up from the bottom to make it easy to change babys diaper. Designed by a nurse. 100% Cotton. Soft, stretchy cotton knit. 0.7 TOG. Machine wash warm and tumble dry low. US patents 11,812,795 & D833,613 with patents in EU, UK, CA, CN, JP and other countries.