Snug for winter. Best for sleeping in 17-23 degree room temperatures. Skin-friendly, breathable natural fibres 2-way zipper for easy diaper change Organic stretch cotton with an inner layer of super soft stretch bamboo viscose terry at the top and filled with organic cotton at the bottom Armhole snaps help transition baby to arms free The ergoCocoon 'no origami' baby Swaddle Sleep Bags are designed to be both easy to use and difficult to escape from. The simple zip up design will keep baby snug and securely swaddled without the need for complicated wrapping. The 2.5 TOG ergoCocoon Swaddle Sleep Bag is designed for Winter temperatures and is made from an Organic Cotton jersey outer layer and is filled with 100% organic cotton for warmth. Arm snaps allow arms to be free or tucked in, and the 2-way zipper allows for quick and easy diaper changes.