Created with machine washable cotton fabric and a soft, flannel lining as well. The inner layer is PUL fabric (Polyurethane Laminate) which create a waterproof barrier to catch any urine from seeping through if your dog leaks through a sanitary pad. It has a 2″ wide secure Velcro fastener to keep it snug and tight. You place a sanitary napkin inside the center of the belly band for absorbency – changing the pad as necessary.