Marcus plastic coin holders are made from an inert polystyrene and are archival safe. Just insert a coin into the holder and snap the two sides shut. Each plastic holder has a crystal clear center window and a frosted outer edge. All Marcus holders have an air tight double seal and can be opened and reused without damaging the case or coin. These plastic 2x2s can be conveniently stored in any of our 2x2 coin boxes.