16GB KIT (4 x 4GB) For Apple iMac Series 2.66GHz Intel Quad Core i5 - (27-Inch) (DDR3 - Late 2009) 2.8GHz Intel Quad Core i7 - (27-Inch) (DDR3 - Late 2009) 3.06GHz Intel Core 2 Duo - (21.5-Inch) (DDR3 - Late 2009) 3.06GHz Intel Core 2 Duo - (27-Inch) (DDR3 - Late 2009) 3.33GHz Intel Core 2 Duo - (21.5-Inch) (DDR3 - Late 2009) 3.33GHz Intel Core 2 Duo - (27-Inch) (DDR3 - Late 2009). SO-DIMM DDR3 NON-ECC PC3-8500 1066MHz RAM Memory. Genuine A-Tech Brand. 16GB KIT (4 x 4GB) SO-DIMM DDR3 NON-ECC PC3-8500 1066MHz RAM Memory Genuine A-Tech Memory Lifetime Warranty Toll Free Technical Support 1-866-557-4527 Designed For Apple iMac Series. (See Compatibility List Below)