The original Stokke Sleepi mattress is a specially developed polyurethane foam mattress manufactured to the same quality as mattresses for premature babies and medical equipment. The high-quality foam mattress offers excellent breathing and ventilation properties. It is very stable and retains its shape and form. The quilted cotton top sheet with mesh material on the underside increases ventilation and comfort. It offers your child a warm, insulated feeling. Cleaning is easy: the cover is machine washable up to 40°. The Stokke Sleepi mattress is easy to clean.