Supplementary cards can be swiped through POS machines, or they can be bound to Alipay and WeChat to enjoy fast payment. At the same time, they can pay attention to the rich activities carried out by BOC through the official account of "China Bank Credit Card" WeChat and colorful life APP. The main card and the secondary card (secondary card) of a credit card are subordinate. The secondary card is based on the name of the main card, has the same function and shares an account, but it only needs to be on the main card when repaying. The main card and the auxiliary card can share the credit limit of the main card, and the consumption records are uniformly included in the bill of the main card.