The heart of the Natural Rubber Crib Mattress is the 6 inch core of Firm Natural Rubber that provides that perfect feel for a newborn baby. Surrounded with quilted layers of wool and encased in an organic cotton fabric, the Natural Rubber Crib Mattress is extremely durable and resilient. Crib mattress size is 28" x 52" Extremely durable, flexible and resilient, the mattress molds to your child's body. It is naturally resistant to moisture build up and is naturally antibacterial and hypoallergenic. Specifications: 100% Organic Cotton fabric cover, layer of pure wool act as a flame retardant & contains 6 inch Firm Natural Rubber core.