CPO (Certified Pre-Owned) refers to “Officially Certified Pre-Owned Devices,” which are used Apple phones that have been strictly tested, refurbished, and certified by the official or authorized institutions. The quality is close to that of a new device. These devices must undergo standardized processes such as functionality testing, appearance restoration (e.g., replacing the casing/battery), and system resetting to ensure there are no hardware faults or software issues. They are also equipped with original or compatible accessories and come with official or third-party warranty services (typically ranging from 90 days to 1 year). The packaging or system information will include a “certified” label to distinguish them from regular used products.