HALO SleepSack wearable blanket: The Safer Way to Sleep The HALO SleepSack wearable blanket replaces loose blankets in the crib that can cover your baby’s face and interfere with breathing. In addition to helping your baby sleep safer, the HALO SleepSack wearable blanket helps your baby sleep better, too. It is a warm cuddly blanket they cannot kick off; ensuring baby sleeps soundly throughout the night. Used in hospital nurseries nationwide, the Halo SleepSack wearable blanket is the #1 choice of hospital nurseries and is recognized as "Hip Healthy" by the International Hip Dysplasia Institute. HALO also proudly supports non-profit organizations like First Candle/SIDS Alliance. Use over regular sleepwear to take the place of loose blankets. 100% cotton interlock. TOG: 0.5. Size small fits 10-18 lbs; size medium fits 16-24 lbs; size large fits 22-28 lbs; size extra large fits 26-36 lbs.