Serta’s Perfect Embrace 4" Mini Crib Mattress 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 (not designed for standard cribs or pack 'n plays). The fiber core, made from recycled materials, delivers a firm yet lightweight sleep space, while the waterproof vinyl cover helps prevent mold, mildew and odor. All Serta crib mattresses are GREENGUARD Gold Certified and meet the strictest standards offered by the Greenguard Environmental Institute, which recognizes products with low chemical emissions, contributing to improved indoor air quality.