HYBRID DESIGN -- Hybrid design featuring both coils, foam, and natural touches for superior support and comfort throughout. 204 premium steel coil system that creates ultimate firmness for toddlers. Sealy mattresses are tagged with a firmer infant side and softer comfort side for toddlers on the tag SOFT COTTON COVER -- Luxurious cotton cover that is breathable on baby’s skin with a waterproof barrier is designed underneath the cotton cover, pvc-free mattress. 2-STAGE FIRMNESS -- On the infant side, a luxurious organic cotton and firm layer provide comfort and stability. The toddler side features a soybean memory foam layer for comfort. PREMIER SUPPORT -- Enhanced with border wire along the edges for support. 6 Ever edge strength pillars for corner & side support just like an adult mattress. SAFETY & QUALITY TESTED -- Firmness, durability and crib fit tested, passes American Society for Testing and Materials (ASTM) Crib Mattress Standards, this entire crib mattress is GREENGUARD Gold certified for indoor air quality and tested for chemicals.