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 21.5-Inch (Late 2012) Review | PCMag
iMac RAM upgrade: Here's an affordable way to improve multitasking - CNET
Install memory in an iMac - Apple Support
CMS 32GB (4X8GB) DDR3 12800 1600MHz Non ECC SODIMM Memory Ram Upgrade Compatible with Apple® iMac Core I7 3.4 27-Inch (Late 2012) - A6 at Amazon.com
Apple iMac "Core i5" 2.7 21.5-Inch (Late 2012), 1 TB HD, 8GB RAM, OS 10.11.6 - Imagine41