Apple Computer , iMac 21.5-inch 3.06/3.33 GHz Core 2 Duo (E7600, E8600), iMac 21.5-inch 2.66 GHz Core i5 (i5-750), iMac 21.5-inch 2.8 GHz Core i7 (i7-860), Order Number, MB950LL/A, MB952LL/A, MB953LL/A, MC507LL/A, BTO/CTO, Model Number, A1312, A1311, Part Name, Memory 4GB DDR3 1066 MHz, Manufacture Part Number, N/A, EMC Number, EMC 2309, EMC 2308, EMC 2374, EEE Code, N/A, Compatible Apple Computer, iMac (27-inch, Late 2009), iMac (21.5-inch, Late 2009), ,
Order you product here: 661-5309 Memory 4GB DDR3 for iMac 21.5 & 27 inch Late 2009 A1312 A1311 MB950LL/A, MB952LL/A, MB953LL/A, MC507LL/A, BTO/CTO, 661-5309
source http://info.applepartsellers.com/661-5309-memory-4gb-ddr3-for-imac-21-5-27-inch-late-2009-a1312-a1311-mb950ll-a-mb952ll-a-mb953ll-a-mc507ll-a-bto-cto