Cocoons are double-sided. They have a mattress-sponge in the middle and thanks to that they are soft for a baby. Cocoons are extremely practical. External edges "shaft” is detachable from the bottom of the nest, which makes it easier to wash. In this way, they have two parts that can be washed separately. You can easily wash the bottom part and you do not have to do that with all he washing. In addition, the bottom part is still dismountable, it means that we move the zipper way and take off the pillowcase, remove the sponge from the inside and we only wash the pillowcase.