Designed to fit the unique oval shape of the Stokke® Sleepi Bed, Naturepedic's crib mattress has been carefully calibrated for both maximum comfort and easier cleanup. The organic cotton and foam core is cushy yet supportive for growing bodies, and has a wipe-clean waterproof surface made from food-grade sugarcane. It's wrapped in a cover with a 3-dimensional woven fabric that lets air flow through, as well as a thin waterproof backing that provides extra protection from leaky diapers.