Apple Posts iMac (Late 2013) Memory Specifications
Apple iMac 21.5" Core i5-4570R 2.70 GHz, 8GB RAM, 1TB HDD, 10.15.6 Lat – Pc Retro Shop
Memory Upgrades for iMac 21.5-Inch 2012 - Late 2013
parts-quick 16GB 2 X 8GB Compatible Memory for iMac 27" inch 3.2GHz Quad Core Intel Core i5 Late 2013 ME088LL/A 1600MHz DDR3 (PC3-12800) SO-DIMMs RAM at Amazon.com
Apple iMac 21.5" All-in-One Desktop Core i3-3225 3.3GHz 4GB RAM 500GB HDD Mac OS Mojave Early-2013 w/ Keyboard & Mouse ME699LL/A
A-Tech 32GB Kit (4x8GB) RAM for Apple iMac (Late 2012, Late 2013, Late 2014, Mid 2015) | DDR3 1600MHz PC3-12800 SODIMM 204-Pin Memory Upgrade at Amazon.com
Apple iMac 27" All-In-One Computer, Intel Core i5, 8GB RAM, 1TB HD, Mac OS, Silver, ME088LL/A (Used) - Walmart.com
How to Upgrade Memory in a 27-inch iMac (Late 2012-2013) iMac13,2 and iMac14,2 - YouTube
A-Tech 8GB RAM for Apple MacBook Pro (Mid 2012), iMac (Late 2012, Early/Late 2013, Late 2014, Mid 2015), Mac Mini (Late 2012) | DDR3 1600MHz PC3-12800 SODIMM 204-Pin Memory Upgrade at Amazon.com
Amazon.com: Apple iMac 27in Late 2013 A1419 3.5ghz 8gb RAM 1TB HDD El Capitan (Renewed) : Electronics
Install memory in an iMac - Apple Support
Memory upgrade: Apple iMac 2012/2013/2014 (Howto)
16GB -2x8GB Memory Ram Upgrade 21.5" Apple iMac-13.1 Core i3 3.3GHz Early 2013 | eBay
iMac RAM upgrade: Here's an affordable way to improve multitasking - CNET
iMac 2013 Model Ram Upgrade - YouTube
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
CMS 32GB (4X8GB) DDR3 12800 1600MHz Non ECC SODIMM Memory Ram Upgrade Compatible with Apple® iMac Core I5 3.2 27-Inch (Late 2013) Me088Ll/A - A6 at Amazon.com
21.5 inch late 2013 iMac - RAM upgrade - Apple Community