The Original Bamboo Sleep Bag ™ The one that started it all: Our most-loved, best-selling sleep bag. A wearable blanket that helps baby fall asleep (and stay asleep), so you’re not up all night. Designed to be safe sleep, diaper change friendly, temperature-regulating, and so soft you’ll have to touch it to believe it. Exterior: 97% Bamboo Rayon, 3% Spandex Filling: 100% Polyester Highly breathable J-shaped double zipper Use as a wearable blanket over pajamas for safer, cozier sleep Due to lack of quilting the 0.5 TOG Sleep Bag tends to run bigger and have more stretch. We recommend following our fit guide/rules found in the blog here to determine if it is the correct fit.