BreathableBaby Eco Core 250 Crib Mattress, Dual Side, Firm Side Reversible for Infant/Baby and Soft Side for Toddler, Lightweight, Non-Toxic, Water and Stain Resistant, no VOCs or chemicals, Standard 52”x28” The Eco Core 2-Stage Dual-Sided Crib Mattress provides 2-Stage support. One side provides a firm sleep surface to support babies up to 12 months of age and one side provides a softer sleep surface for toddlers. Our crib mattresses are designed to help little ones sleep safe and sound. We start with an eco-friendly, poly fiber core and cover it with a completely hygienic, easy-to-clean cover. Size: Standard Crib. Gender: unisex.