Airport Express difference between MC414LL/A and MC414Z/A?
It is to do with the difference between the power cable shipped with it and possibly some regional legal restrictions.

The model number is MC414.


MC414Z/A is the European variant.
MC414LL/A is the US variant.
MC414C/A is the Canadian variant.
MC414J/A is the Japanese variant.
MC414B/A is the UK variant.


etc...