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
Apple iMac (A1312) 27 Inch High Sierra Intel 2.7Ghz i5 1TB HDD 16GB RAM Mid 2011 | eBay
How to Upgrade iMac RAM (21.5" and 27" Aluminum): EveryMac.com
How to upgrade RAM on iMac 21.5" 2011 - YouTube
Memory Upgrades for Apple iMac 2011 Up to 32GB
How to Upgrade iMac RAM (21.5" and 27" Aluminum): EveryMac.com
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
Install memory in an iMac - Apple Support
Install memory in an iMac - Apple Support
32.0GB OWC Memory Upgrade Kit For 2010-2011 Apple iMac