This Lullaby Earth two-stage mattress was designed to provide support and comfort for growing little ones. It includes a firmer side that's perfect for babies and a cushioned firm side that's just right for toddlers. The square corners allow the mattress to fit securely in cribs, while the reinforced edges are strong enough for bouncing toddlers. The mattress weights just seven pounds, so you can quickly and easily change your crib bedding. Plus, it's made from food-grade polyethylene and 100% pete, which means it's free of common potential allergens and harmful chemicals.