The #1 choice of 1,700 hospitals in the United States, 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 a 2-way zipper for easy diaper changes and a roomy sack design that's recognized by the International Hip Dysplasia Institute as promoting healthy hip development. 100% cotton TOG: 0.5 HALO created the first SleepSack over 20 years ago with both safety and comfort in mind.