All Marcus holders are made of inert Polystyrene that will not harm coins, these holders have a clear center window for viewing the coin and a frosted outer edge. A unique airtight double seal provides excellent long-term protection for your collection. They can be easily opened and reused. Storage is convenient as they can be stored in any of our 2x2 storage boxes or Lighthouse 2x2 pocket pages. Use these complimentary products to take your collection to the next level.