Lightly quilted with sleeves and 4-way stretch cotton to help give babies a snug fit without overheating. Snug upper body allows for easier post-swaddle transition. Roomy sack design supports continued healthy hip development. Features a 2-way zipper for easy diaper changes. Unique sleeve design helps reduce startle reflex without overheating Breathable 100% Cotton 4-way stretch for snug, comforting fit TOG: 1.5 The HALO SleepSack Easy Transition helps control the moro reflex for babies who no longer like to be swaddled, but still need a bit of security around their arms.