The KeyGift Cards import process is used to import KeyGift Card records (mainly to add the valid card numbers and possibly balances). Since the Card Numbers must be unique, Merge is the only method available to be used and can be set up to add new card numbers by enabling the Add New Items import setup parameter. If the imported balance is less than 0, it is automatically set to 0 instead. If importing any of the Time fields, the Date field must also be imported.
See:
Data Importer Contents