Cork
Cork is a natural, lightweight, and non-metallic material commonly used as insulation and for cushioning applications. Cork sheets and strips provide material for gaskets, shipping and spacer pads, protective backing, wall coverings, and bulletin boards. They are also often used as flooring underlays and sound-dampening tiles. Tapered cork serves as stoppers for commercial beverage bottles and laboratory glassware as well as end plugs for metal piping during concrete pouring.