Serta's Sparkling Sky 4-inch Mini/Portable Crib Mattress by Delta Children was designed with your baby's health, safety, and comfort in mind. It delivers all the benefits of a full-sized crib mattress in the convenience of a smaller size to fit mini cribs and portable cribs. Built with a firm, hypoallergenic fiber core made from recycled bottles, it delivers the perfect firmness level for newborns to grow and develop while helping save over 150 bottles from the landfill-great for babies and great for the environment! The waterproof vinyl cover blocks wetness to aid in preventing mold, mildew and odor, and is easy to clean, just wipe clean with warm water and mild soap. And that's not all, the Sparkling Sky 4-inch Mini/Portable Crib Mattress by Serta is extremely lightweight which makes changing the sheets or flipping the mattress a cinch. Fits most mini and portable cribs (NOT designed for standard cribs or Pack 'n Plays). All Serta crib mattresses are GREENGAURD Gold Certified and meet the strictest standards offered by the Green guard environmental Institute, which recognizes products with low chemical emissions, contributing to improved indoor air quality.