Sealy Baby Posturepedic infant and toddler crib mattresses provide one-of-a-kind targeted support with the Posturepedic advanced zone support system. The targeted areas create support and comfort where infants and toddlers need it most. Center zones target the Sweet spot, where infants are placed in their cribs, offering enhanced firmness in the middle of the mattress. Comfy layers are added to the toddler side plus extra head and foot support for active toddlers. The Sealy Baby Posturepedic grace Hybrid model is upgraded as a coil and foam "Hybrid" Similar to adult mattresses. This offers extra comfort and pressure-relieving feature like the soy-enhanced memory foam cushioning that safely senses and responds to your child's movement for contouring comfort. American-made coils and foam are tested for lasting durability. Measures 51.63 x 27.25 x 5.75. The Sealy SafetyCase Protective Crib Mattress Encasement provides a 100% waterproof barrier to guard against leaky messes and spills and is machine washable and dryer friendly for easy cleaning. The SafetyCase offers a square corner design that fully encases both square and round corner crib mattresses and can easily zip around even the thickest foam or innerspring baby mattress. Use underneath crib mattress pads and fitted crib sheets to create a well-protected and cozy sleeping environment for baby. We recommend that new parents purchase 2 crib mattress encasements, so you always have a fresh, dry one on-hand while the others are in the wash.