Giffgaff and Talkatone are two high-quality overseas mobile phone card products. They have the advantages of free application, low-cost number preservation, and comprehensive functions. They can be used to register overseas applications such as Telegram and ChatGPT, send and receive overseas text messages, and apply for overseas bank cards. The registration and usage methods are explained in detail. Giffgaff and talkatone phone card registration, physical sim card activation, recharge payment, number preservation