That's a magnetic stripe. When a cardholder uses a credit card to make a large amount of consumption, the issuing bank will pay the consumption funds of the goods (or services) purchased by the cardholder to the merchant in one lump sum, and deduct the consumption funds from the cardholder's credit card account in stages according to the cardholder's application, and the cardholder will repay according to the monthly recorded amount.

In the past, credit card installment mainly included bill installment and single consumption installment, and banks usually charged corresponding handling fees according to the number of installments. Whether it is bill installment or single consumption installment, the premise is to generate consumption behavior first, and then the bank will set installment repayment for the generated credit loan.