Moonlight Slumber Naturals All-in-One Mattress Crib Coverlet is made of premium organic cotton fabric, then tailored to wholly encase (top, bottom and sides) a standard crib mattress. It has a zipper partially around the outside edge of the dropped seams allowing easy mattress dressing. Twice the cover, twice the protection and no chance of slippage or bunching. Fully machine washable (and dryer safe).