Sealy Baby Naturalis 2-Stage Dual Firmness Hybrid Waterproof Standard Toddler & Crib MattressA hybrid crib and toddler mattress that offers multiple layers of natural comforts combined with proper support features: organic cotton, natural cotton, soy enhanced memory foam, and American made steel innerspring coils. Plus, an airy, luxurious cotton fabric top with waterproof barrier that is essential for your babys mattress and an airflow pocket to allow the mattress to breathe. Measures 51. 63 x 27. 25 x 5. 75 and fits both USA standard size