A-Tech 32GB Kit (4x8GB) RAM for Apple iMac (Late 2012, Late 2013, Late 2014, Mid 2015) | DDR3 1600MHz SODIMM PC3-12800 204-Pin SO-DIMM Max Memory Upgrade at Amazon.com
How to Upgrade iMac RAM: 2012-2022: EveryMac.com
Apple iMac 21.5" Late 2013 Core i5 2.7GHz 8GB RAM 1TB HDD MacOS Big Sur 11.5.7 | eBay
SOLVED: Need more ram for iMac 21.5 late 2013 - iMac Intel 21.5" EMC 2638 - iFixit
How to upgrade RAM iMac late 2013 21.5inch - break & fix MOVIE - YouTube
21.5" iMac Has No User-Upgradable RAM; 27" Has Four Accessible RAM Slots - MacRumors
16GB Memory Upgrade Kit for 2012-2013 iMac 21.5-Inch
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
Adamanta 16GB (2x8GB) Apple Memory Upgrade DDR3L 1600MHz SODIMM Compatible for iMac (Mid 2011, Late 2012, Early/Late 2013, Late 2014, Mid 2015), MacBook Pro (Early/Late 2011, Mid 2012), Mac Mini at Amazon.com
Upgrade RAM Apple iMac 21.5 slim A1418
Install memory in an iMac - Apple Support
Mac RAM Upgrade, Best iMac Memory Upgrade – Best Reviews