The Swaddelini sleep sack is the only seamless 3D knit sleep product on the market. The swaddelini is engineered with Hug Technology® built into the chest and arms area to give the sensation of a hug all night long. This gives babies a calming sensation so they can learn how to self soothe after experiencing natural moro-reflex and active sleep which are good for their brain development. There is an easy access diaper opening at the bottom so the feet stay warm and provides easy diaper changing access so there is no need to take the swaddle off during the night! If you have a little Houdini, this is for you!