You must match the Model Number (e.g., A2633) and the Storage Capacity (64GB, 128GB, etc.) to the buyer's specific regional requirements. Be aware of Version Differences: for example, US versions may include mmWave 5G antennas, while other regions do not. Ensure the motherboard is Factory Unlocked to support global GSM/CDMA bands. Additionally, confirm if the board is a Single SIM or Dual Physical SIM version, as this varies by market (e.g., Hong Kong/China versions often feature dual physical slots).