The Joovy Room Waterproof Sheet is fitted and designed to protect the Room's mattress.This sheet consists of a high quality thread count cotton top with an absorbent padded layer, a waterproof barrier, and finally a polyester layer with elastic all around the bottom.The sheet protects against bacteria, which can degrade fabric and lead to stains and odours.The top is fully waterproof, so you never have to worry about spills and stains seeping through to the mattress.Machine wash and dry.