This is the numeric PROM/EEPROM-encoded card-type code UCS Manager reads back from a physical IOM and matches against this catalog entry to positively identify the exact model installed, rather than relying on the PID string alone. It is a low-level identification code intended for UCS Manager's internal matching logic rather than something an admin typically reads directly, but it is the ultimate source of truth for model identification during discovery. For example, a specific promCardType value maps uniquely to a UCS-IOM-2408, letting UCS Manager resolve the model even if the PID string were ever ambiguous.