There are generally two forms of card packs, one is a page-turning type, just like a book page; the other is a rotating type. In terms of materials, leather (animal skin) and artificial leather (pu, pvc) are the most common ones, just like wallets, suitable for carrying around.

In modern life, more or less people have to deal with cards, such as various IC cards, bank cards, supermarket cards, shopping cards, membership cards, etc. So many cards are not easy to store, prone to confusion, and often bring a lot of unnecessary trouble. The card package appears to manage so many cards, which can be said to be a product of the modern economy.
In addition to being able to manage various cards more conveniently and quickly, some card cases can also play a role in radiation protection, so as to avoid the inconvenience of card elimination tapes.