iMac (21.5-inch, Mid 2011)

Model numbers:A1311
Order numbers:MC309LL/A, MC812LL/A
Model Identifiers:iMac12,1
21.5" LCD; 2.5/2.7 GHz (Core i5) / 2.8 GHz (Core i7); 6 MB (2.5 and 2.7 GHz) 8 MB (2.8 GHz) on-chip shared L3; PC3-10600 (1333 MHz)