Serta's Perfect Slumber Firm Crib & Toddler Mattress will grow with your baby from infancy to toddlerhood. Built to fit both standar-size cribs and toddler beds, it features a firm high-density thermo-bonded fiber polyester core for the supportive sleeping surface your baby needs. The labeled infant and toddler sides provide the ideal support and comfort for each age range. The toddler side is outfitted with an additional comfort layer for a deluxe sleeping surface. Finished with square corners to help create a secure fit inside the crib, the mattress boasts a lightweight design that makes changing the sheets easy. From the brand that has been leading the way in mattress innovation and technology for more than 80 years, this Serta crib and toddler mattress deliver the same quality craftsmanship and attention to detail as the rest of the company's acclaimed mattresses.