Stripe Classic Blue Sleep Bag Baby's First Mist Blue Baby Sleeping Sack Crate & Kids Blue Stripe Cotton Sleep Sack Baby's First Blue Sleep Sack, 12 18 Months + Reviews Crate & Kids Canada Sleep Bag for Baby Cotton Sleep Sacks Little Unicorn USA. HALO SleepSack is the original wearable blanket for safe sleep, designed to help babies get better, longer sleep. As the next step after swaddles, it ensures a smooth transition with its zipper for easy diaper changes and a roomy, extra long sack that supports hip health and extends use. Crafted from breathable 100% cotton fabric, it offers cozy quality comfort your baby will love.