Nook presents the worldÂ’s most considered infant mattress, made lighter. New dual air layers foster oxygen flow inside the mattress. The certified non-toxic foam core provides support while the superior softness of all-natural eucalyptus provides comfort. 2-sided design ensures a firm and breathable sleep space for infants. Flip the Pebble Lite over for a plush yet equally breathable toddler mattress.Cover materials: eucalyptus, organic cotton, zinc, polyester, easy-close nylon zipper Core materials: non-toxic certipur foam, pete Care instructions: machine wash cover in cold water with a mild detergent, and tumble dry. Do not use fabric softener or chlorine bleach. We recommend the use of a top sheet to prolong the life of your pebbleCollection: Pebble Lite Dimensions: 53 x 28 x 4 Weight: 16 lbs