High density thermo-bonded core provides firm support, Lightweight and durable for long-lasting use throughout your child's development, Outer Cover: Vinyl laminated with Polypropylene, Product Dimensions: 52.5"L x 27.5"W x 5.5"H - Thickness: 5.5 inches, The Safety 1st Heavenly Dreams mattress has achieved GREENGUARD GOLD Certification