The purpose of this product is to protect your mattress naturally from every day wear and tear. Made with slightly felted and tightly woven wool that is naturally water repellent. The napped surface absorbs moisture and keeps dampness from getting through. So whether it's sweating or children in the bed who sometimes go in the night, you're covered. This is an essential item for parents of little ones and are available in sizes from twin all the way to king. Made with thick felted 100% woven organic wool textile. It lays flat on top of the mattress without straps and is held in place by the fitted sheet. This is a natural replacement for a vinyl plastic or synthetic mattress cover.