The original wearable blanket replaces loose blankets in the crib for a safer environment; the #1 choice of hospital nurseries to promote safe sleep Made from 100% cotton interlock fabric with a TOG rating of 0.5, offers just the right comfort for warmer seasons or climates; can be layered with warmer sleepwear for cooler temperatures; double knit construction of cotton interlock fabric makes it extremely soft and a little stretchy, perfect for baby sleepwear Unique, roomy sack design recognized by the International Hip Dysplasia Institute as "hip healthy" - allows room for kicking but cannot be kicked off, so Baby stays warm and safe all night Inverted zipper opens from the bottom for easy diaper changes; sleeveless to reduce the risk of overheating; arm and neck openings sized for a safer fit