32GB (2X16GB)Ram Upgrade for iMac Late 2012 21,5 inch? | MacRumors Forums
Install memory in an iMac - Apple Support
What Does It Take To Upgrade a 2012 iMac 21.5"?
iMac RAM for Model 13.2 to 15.1| DDR3-1600MHz | 4GBx2 | MacMemory.com
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