Our Safety 1st Transitions Crib & Toddler Bed Mattress is the only mattress you'll need! This dual-purpose mattress is built to grow with your child: firm for babies on one side and extra cushioned for toddlers on the other. The mattress is made with a high-density thermo-bonded fiber core and covered with a waterproof and stain resistant non-removable cover that wipes up easy for quick clean ups. The Transitions mattress is lightweight and durable and fits standard crib with internal measurements of 285/8 in. X 53 in. This Safety 1st mattress is made without the use of flame retardant chemicals and has achieved GREENGUARD Gold certification, meeting the standard for low-chemical emissions for a sleep environment that's always safe and sound. Assembled in Canada, this Safety 1st mattress comes with a 10-year limited warranty.