iMac 21.5 part numbers

Could anyone shed some light on the iMacs product numbers? I'm considering to buy a new iMac 21.5 and was sniffing around for some good deal

I found this quite comprehensive list, but I couldn't work out what's the difference between MB413LL/A, MC413XX/A and MB950XX/A

Cheers guys

Anyone?

Weaselboy said:

http://www.autographsystems.com/autsys/appleproducts.html

Second hit when I google your first product number.

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Cheers Weaselboy, I think I saw that page too, but MC413XX is not there?

Weaselboy said:

http://support.apple.com/kb/HT1758

The XX is a country variable. So MC413LL/A is USA for example.

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I got that. And I've got Google too. But what is the specs difference between MC413XX/A and MB413LL/A?