OWC 16GB (2x8GB) ram Upgrade PC3-12800 DDR3L 1600MHz sodimm 204 Pin CL11 Memory Upgrade Kit Compatible with Late iMac, Mac Mini, and MacBook Pro Computer at Amazon.com
16GB -2x8GB Memory Ram Upgrade for 27" Apple iMac-12.2 Core i5 2.7GHz Mid 2011 | eBay
Apple iMac 2011 Memory 4GB DDR3 1333MHz PC3-10600 204-Pin
How to upgrade RAM on iMac 21.5" 2011 - YouTube
2011 Apple Mac Mini Imac Macbook Pro Memory Ram 8gb 4gb 16gb Ddr3 1333 - Rams - AliExpress
Timetec 16GB KIT(2x8GB) Compatible for Apple DDR3L 1600MHz for Mac Book Pro(Early/Late 2011,Mid 2012), iMac(Mid 2011,Late 2012,Early/Late 2013,Late 2014,Mid 2015), Mac Mini(Mid 2011,Late 2012) MAC RAM at Amazon.com
install - Installing and Upgrading Ram on a mid 2011 iMac (different size RAM) - Ask Different
Memory RAM Upgrade for Apple iMac 21.5-inch Mid 2011 4GB/8GB DDR3 SODIMM | eBay
A-Tech 8GB (2x4GB) RAM for Apple MacBook Pro (Early/Late 2011), iMac (Mid 2010, Mid 2011, Late 2011), Mac Mini (Mid 2011) | DDR3 1333MHz PC3-10600 204-Pin SODIMM Memory Upgrade Kit at Amazon.com