64GB Memory Upgrade Kit for 21.5-inch Apple iMac 2017
Apple iMac (21.5-inch, Retina) – Intel Core (2017) – Maxandfix
Apple iMac 21.5-inch 2.3GHz Core i5 (Mid 2017) | mac of all trades
Upgrade your iMac with OWC, 2017 4K Retina Edition
2017 iMac SSD upgrade & Speedtest - YouTube
Apple 21.5" Certified Refurbished iMac 4K Intel Core i5 2.3GHz 8GB Memory 256GB SSD (2017) MHK03LL/A - Best Buy
Refurbished: Apple A Grade Desktop Computer iMac 21.5-inch (Retina 4K) 3.0GHZ Quad Core i5 (Mid 2017) MNDY2LL/A 24 GB 2 TB SSD 4096 x 2304 Display Mac OS Includes Keyboard and Mouse - Newegg.com
Upgrade/Install a PCIe SSD in a 21.5-inch Apple iMac