Without index cards, all index systems would make no sense. It is only with index cards that information can be recorded, filed and stored. Index cards are therefore available in all conceivable DIN formats, so that suitable cards can be found for every card index box and tray or for every card index box. Cards are not only available in different sizes, they also differ in colour, type of liner and grammage. Some index cards are as thick as cardboard, others as thin as paper. Depending on the purpose, one or the other is more suitable. The thickness of the cards also determines how many of them fit into an index system. Index cards are sometimes included in the delivery of HAN products, but they can also be ordered as accessories.