Apple iMac 27" 2011 Intel Core i5 2.7GHz 1TB HDD 4GB RAM - A Grade Refurbished | Groupon
Amazon.com: 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 : Electronics
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
Timetec Hynix IC 16GB KIT(2x8GB) Compatible for Apple DDR3 1333MHz PC3-10600 for Early/Late 2011 13/15/17 inch MacBook Pro, Mid 2010 Mid/Late 2011 21.5/27 inch iMac, Mid 2011 Mac Mini(16GB KIT(2x8GB)) - Newegg.com
iMac RAM Models 11.3 (i5 and i7 only) to 12.2 (8GBx4) | MacMemory.com
Apple Launching Pilot Program Allowing Repairs of Soon-to-Be Vintage Mid 2011 iMac in United States - MacRumors
Install memory in an iMac - Apple Support
I recently purchased 2011 21.5 iMac (Mid-2011) and I'm obsessed. : r/mac
How to Upgrade iMac RAM (21.5" and 27" Aluminum): EveryMac.com
How to upgrade RAM / Memory on a 2010 iMac Core i3 i5 i7 (21.5in & 27in) - YouTube