Organic Cotton. The ergoCocoon baby swaddle sleep bag is designed to be easy to use and difficult for wiggly babies to escape from. Bag has a two-way zipper and zips up and will keep baby snug and securely swaddled without the need for wrapping. The 1.0TOG is made for Autumn/Spring temperatures and is made from organic cotton and bamboo. Poppers in the armholes help baby transition to arms free. Highly breathable and antibacterial.