evolur Sleep Comfort Balance plus with Antimicrobial copper Fiber mattress provides the support babies and toddlers need for good night sleep. Our stage sleep technology mattress inner core is constructed with extra firm antimicrobial fiber for the infant side, a comfort layer for a toddler, a soft touch fabric with inverted seams, and a waterproof protection barrier. This mattress is topped with an insulated layer of chemical-free fire barrier for ultimate comfort. evolur stage technology mattress is built to fit both a standard full-size crib and toddler bed. Turns out, copper does an amazing job of maintaining freshness.