Wearable blanket for safe sleep Allows for easy diaper changes Scratch-free zipper covers 100% polyester micro-fleece 1.0 TOG Medium fits ages 6 -12 months, height range from 26"-30", weight range from 16 to 24 lb HALO® created the first SleepSack® over 20 years ago with both safety and comfort in mind. Our original wearable blanket with sleeveless design nestles baby like a soft blanket without the risk of sleep-related dangers. Signature "Back is Best" embroidery is a gentle reminder to place baby in the recommended sleep position. Features an inverted zipper for easy diaper changes and a roomy sack design that is recognized by the International Hip Dysplasia Institute as promoting healthy hip development.