Timetec Hynix IC DDR3L 1600MHz PC3L-12800 SODIMM Compatible with Apple 2011, 2012, 2013, 2014 MacBook Pro, iMac, Mac mini (16GB Kit(2x8GB)) - Newegg.com
install - Installing and Upgrading Ram on a mid 2011 iMac (different size RAM) - Ask Different
Apple iMac 2011 Memory 4GB DDR3 1333MHz PC3-10600 204-Pin
NEMIX RAM 32GB (4x8GB Upgrade) DDR3-1333 PC3-10600 204-Pin SODIMM Memory for Apple MacBook Pro Early/Late 2011, iMac Mid 2010 27 inch 4-Core, iMac Mid 2011 21.5/27” , Mac Mini Mid 2011 at Amazon.com
21.5” mid-2011 iMac wires? Finally trying to upgrade my RAM and these wires are blocking the slot — did get an iMac with poor build quality? What can I do? : r/mac
Timetec 32GB KIT(4x8GB) Compatible for Apple DDR3L 1600MHz PC3L-12800 CL11 for iMac (Mid 2011, Late 2012, Late 2013, Late 2014 Retina 5K, Mid 2015 Retina 5K) SODIMM Memory Module MAC RAM Upgrade at Amazon.com
How to Upgrade iMac RAM (21.5" and 27" Aluminum): EveryMac.com