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 pro vides 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 stitc hing. Six 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 bed