The Serta Nightstar Super-Firm Mattress uses heavy-gauge coils to provide extra firm, balanced support to your little one. The inside layer is made of an exclusive Serta Fireblocker material for gentle sleeping and safety. An ortho-insulated layer provides additional support and firmness. This mattress has balanced support from the full-perimeter border wire that creates firm edges, even when baby stands on it. The security of these edges is assured through heavy-duty cloth binding with lock stitching. Four vents allow airflow to keep baby's sleeping environment fresh. A heavy laminated cover featuring the Serta sheep provides anti-bacterial and anti-microbial protection and can easily be wiped clean with a damp cloth. This mattress also fits toddler beds.