The Stokke Sleepi Colgate-made foam mattresses are ranked number 1 by Consumer Reports. NaturesWeave open air construction, for maximum airflow and pressure relief. Firm, strong, and durable with a nontoxic cover and waterproof backing. Extra firm polyethylene layer for infant support and safety. Dissipates heat away from baby. Inverted seam design provides a snug fit in the designed Sleepi crib and tight fitting sheets. Made in USA.