Nook Sleep Systems Details Nook - Pebble Lite. The Pebble Lite offers a breathable design which optimizes airflow throughout the mattress, and features a certified non-toxic foam core that provides firm support, eucalyptus fabric which minimizes overheating, and a removable and washable outer layer that makes clean up easy. The Pebble Lite boasts anti-microbial, anti-mite, water and stain resistant qualities. The 2-sided design ensures a firm and breathable sleep space for infants, and, once your infant has grown, simply flip the Pebble Lite over for a plush yet equally breathable toddler mattress. As with all Pebble mattresses, eliminate the need for an additional mattress pad. Nook's state of the art machine-washable, water and stain resistant, super-soft fabric cover makes cleaning up quick and easy, even at 3 a.m. Specs Who: Designed and Manufactured by Nook . Materials: Includes removable, washable Pebble Wrap and certified non-toxic foam core. Composed of Eucalyptus, Organic Cotton, Zinc, Polyester, Easy-Close Nylon Zipper, Non-Toxic Foam Core, PETE. Specs: 28 x 53 x 4 (inches) Weight: 16 lb Features: UL Listed Lamp Type: -- -