The Marketing Part Number (MPN) is code that Apple Inc. uses to classify all of its items in a unique way. An MPN can be used to identify a particular configuration of Apple hardware.[1] MPNs are additionally referred to by Apple as order numbers, and part numbers, and model numbers, but are distinct from Apple's "A number" format of model codes.[2]
Typical Marketing Part Numbers are M8738LL/A for a 20 GB iPod, M9454LL/A for a Power Macintosh G5, and MC605FD/A[3] for a 32 GB European iPhone 4.