Our crib mattresses are made from safe, sustainable materials. All are free from harmful chemicals and tested according to strict safety requirements. Your child will sleep safely – and so will you. The outer cover is easy to remove and is machine washable at 140°F (Hot). A fixed inner cover increases the fire safety of the mattress and makes it easy to put the outer cover back on after washing. It also prevents children from putting mattress contents in their mouth. The zipper of this mattress has a little pocket where you can hide the pull tab from the hands of curious children. The mattress has two different surfaces ‒ one wavy side with medium-firm comfort and one smooth side which is firmer.