This thin mattress pad has a waterproof membrane that protects your mattress from spills and accidents. The cozy cover of the mattress pad surface features soft microfiber on top of a thin layer of down-alternative fill. Diamond quilting keeps the fill in place and improves airflow for a smooth, even, breathable sleep surface. For a secure fit, each corner features a thick elastic that stretches to fit mattresses. Surface: 100% polyester; Backing: 100% polyethylene