OWC SSD Upgrade Kits for 21.5-Inch iMac (2013 - 2019)
iMac 2013 (and later) with NVME SSD? | MacRumors Forums
DIY Bundle - 1TB OWC 6G SSD and HDD Kit for 21.5-Inch iMac
Amazon.com: OWC 1TB Aura Pro X2 NVMe SSD Upgrade Kit Compatible with Select 27" and 21.5" iMac Models (Late 2013 - Current) : Electronics
Apple iMac 21.5" - Late 2013 Reviews, Pros and Cons | TechSpot
I got a FREE 2013 iMac 21.5 with internal upgrades including Samsung evo ssd and 16gigs of ram. Then used open legacy patcher to install Mac OS Venture 13.5 beta. : r/osx
How to Upgrade/Replace the PCIe SSD in a 21.5-inch iMac (Late 2013) iMac14,1 iMac14,3 - YouTube
OWC SSD Upgrade Kits for 21.5-Inch iMac (2013 - 2019)
Amazon.com: Odyson - 1TB SSD Replacement for Apple MacBook Pro 13" A1502, 15" A1398, Replacement for Apple Mac Pro A1481, 21.5" A1418, 27" A1419 (Late 2013-Late 2014) : Electronics