Timetec 16GB KIT(4x4GB) Compatible for Apple DDR3 1067MHz / 1066MHz PC3-8500 CL7 Dual Rank for iMac (Late 2009 21.5-inch / 27-inch) SODIMM Memory MAC RAM Upgrade for iMac 10,1 and iMac 11,1 at Amazon.com
CMS 16GB (4X4GB) DDR3 10600 1333MHZ NON ECC SODIMM Memory Ram Compatible with Apple Imac 27" 2.8Ghz Intel Core I5 Quad Core Mc511Ll/A - A28 - Walmart.com