The Leuchtturm Optima 12-Compartment Numismatic Pouch, reference 309197, pack of 5 units, is a coin filing sheet measuring 50x50mm each. Leuchtturm is a German brand founded in Hamburg in 1917, considered a world leader in collection systems for philately and numismatics, with a catalog of over 6000 items covering more than 140 collection areas. It is made of transparent film free of acids and plasticizers, allowing you to see the coins on both sides without removing them from the sheet and without risk of oxidation from contact with chemicals. It is compatible with the Optima classifiers from the same brand. This 50x50mm reference is suitable for larger diameter coins, such as many commemorative coins.