Give your baby the possibility of dreaming big with Safety 1st Sweet Dreams Ultra Firm Baby Crib Mattress. Made with a high-density thermo-bonded core from polyesters fibers, we promise to deliver optimal support and comfort all night long. Its removable outer cover, made from polyester and rayon on Bamboo, not only provides the ultimate comfy surface but it's also water resistant and easy to clean! The Ultra Firm Baby Crib Mattress fits in any standard crib with internal measurements of 285/8 in. X 53 in. Durable and lightweight, it is made without the use flame retardant chemicals. Enjoy a 10-year limited warranty, guaranteeing comfort for years to come. Assembled in Canada.