Apple iMac 13,1 A1418 2012 Intel Core i5 3330S 2.70GHZ 8GB RAM NO Screen/HDD/OS | eBay
How to Upgrade/Install Memory in a 21.5-inch iMac (Late 2012– Mid 2014) iMac14,1 iMac14,3 - YouTube
DDR3 1600MHZ PC3-12800 SODIMM for Apple iMac 2012 - 2013 (13,2 14,2)
NEMIX RAM 16GB Kit (2x8GB Upgrade) DDR3-1600 SODIMM PC3-12800 for Apple MacBook Pro Mid 2012 / iMac Late 2012 / iMac 2013, Late 2014, Mid 2015, Mac Mini Late 2012 at Amazon.com
RAM Door for iMac 27 2012 A1419 DIY Parts replacement Internal Parts
Harder, better, faster, stronger: A review of the 27-inch iMac | Ars Technica
Memory Upgrades for iMac 27-Inch (2012 - Mid 2015)
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