Our 100% cotton provides a natural, breathable and comfortable surface to sleep on. The absorbent middle layer is enough protection for children and adults. The soft, noiseless, breathable PUL (polyester backed polyurethane) backing is completely waterproof. It is important to us that your Brolly Sheet protector does not contain any PVC or vinyl because from its manufacture to its disposal, PVC emits toxic compounds. Plus PVC and vinyl products can be noisy and make you sweat more.