You get crystal-clear, economical protection for your coins with these self-locking Kointains. Developed by an expert on coin storage, they're used at such prestigious institutions as the Smithsonian and ANA (American Numismatic Association) museums! Kointains are made from a safe, PVC-free plastic that's designed in two pieces, both slightly curved. When the two pieces are snapped together over your coin, the plastic bends outward from the coin's surface - only the edge of your coin comes into contact with the holder! Sold in packs of 100.