How to Upgrade/Install Memory in a 21.5-inch iMac (Late 2012– Mid 2014) iMac14,1 iMac14,3 - YouTube
iMac Ram Upgrade Singapore
* UPGRADE: iMac 21", A1418-A2116
OWC 16GB (2x8GB) ram Upgrade PC3-12800 DDR3L 1600MHz sodimm 204 Pin CL11 Memory Upgrade Kit Compatible with Late iMac, Mac Mini, and MacBook Pro Computer at Amazon.com
A1418 Memory SDRAM 16GB DDR4-2400 for Apple iMac 21.5-inch 27-inch A1419 (Retina 5K 2017)