size small 5-12 lbs SNOO Sleep Sack is the ultra-soft, ultra-easy swaddle sack that helps babies be happier and sleep longer! Made with 100% organic cotton SNOO wings that keep babies safely on the back…for all naps/all nights Special inner arm bands and leg flap keep even little Houdinis bundled all night Perfect for healthy, growing hips (International Hip Dysplasia Institute seal of approval) Extra-quiet Velcro, so light sleepers don’t startle awake with diaper changes Breathable mesh—at shoulders and legs—keeps Baby cool and comfy Arm openings that are easy to unsnap for babies who prefer their arms out Double-zipper—opens from top or bottom—for easy midnight diaper changes To create a continuous groovy design, we made our Tie-Dye SNOO Sack without mesh panels. (That gives you more of our super-soft, all-seasons 100% organic cotton!)