Charga-Plate
An embossed metal tag, much like a dog tag, that American department stores used for customer credit decades before the credit card.
Farrington Manufacturing of Boston started making them in 1928. The plate carried the customer's name and address in raised letters, and the clerk pressed it onto the sales slip exactly as a later imprinter would do with a card. Each plate was good only at the store that issued it.
Every store ran its own credit and its own plate, so a well-off shopper could end up carrying a jangling bunch of them. That was precisely the problem Diners Club in 1950 and BankAmericard in 1958 set out to solve: one card, many merchants, and a third party carrying the risk. The embossing and the imprint, however, survived the move to plastic.