Baby Works Waterproof Mattress and Sheet Protector will protect your childs mattress and keep bed sheets dry throughout toilet training. No more middle of the night sheet stripping. It is 100 percent waterproof with a non slip backing that fits under or over bed sheets to protect mattresses from moisture and staining. The soft quilted poly cotton surface comes with tuck in flaps for a snug and comfy fit on any size mattress. It is highly absorbent bleach-able machine washable and dryer safe too.