The Quiet Nights 4-inch Mini Crib Mattress by Simmons Kids is designed to provide the same comfort and support as a full-size crib mattress, in a scaled-down size. Featuring a hypoallergenic, breathable fiber core made from recycled bottles, it delivers firm comfort that's safe. Its lightweight design makes it easy to change the sheets, maneuver or flip while its waterproof, vinyl cover blocks wetness to help prevent odor. Vinyl cover easily wipes clean with warm water and mild soap. Fits most mini and portable cribs (not designed for standard cribs or pack 'n plays). All Delta Children 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.