The Amazing Baby cotton muslin sleeping sack is perfect when baby is ready to transition from swaddling. The breathable, soft open weave, single layer wearable blanket replaces loose blankets for safer sleep. The premium cotton muslin gets softer with every wash and is appropriate for warmer environments. The handy 2-way zipper zips down from the top making it easy to place baby into sack and also zips up from the bottom making diaper changes easy. Wear over pajamas to replace loose blankets. Exclusive design for Amazon by artist and mom, Lynette Damir. Small fits up to 28". Medium fits up to 32". Large fits up to 35". Machine washable. Designed and manufactured by SwaddleDesigns exclusively for Amazon.