32.0GB OWC Memory Upgrade Kit For 2010-2011 Apple iMac
Install memory in an iMac - Apple Support
Apple iMac 2.5Ghz i5-2400S (Mid-2011) *No HDD/RAM* – MSU Surplus Store
New 16GB 4x4GB Memory Apple iMac (21.5 and 27-inch, Mid 2011) PC3-10600 at Amazon.com
Maximum memory for 2011 iMac - Ask Different
Apple iMac 21.5", Mid 2011, 2.7GHz Intel Core i5, 4GB, High Sierra 1TB SATA HD | eBay
A-Tech 8GB RAM for Apple MacBook Pro (Early/Late 2011), iMac (Mid 2010 27 inch 4-Core, Mid 2011 21.5/27 inch), Mac Mini (Mid 2011) | DDR3 1333MHz PC3-10600 204-Pin SODIMM Memory Upgrade Module at Amazon.com