Exterior: 97% Rayon made from Bamboo, 3% Spandex Filling: 100% Polyester Highly breathable J-shaped double zipper Use as a wearable blanket over pajamas for safer, cozier sleep The one that started it all: Our most-loved sleep bag. Silky soft sleepwear that helps baby fall asleep (and stay asleep), so you’re not up all night. Designed to be soothingly warm, diaper-change friendly, and extra gentle on sensitive skin.