Amazon.com: OWC 1.0TB SSD Upgrade Bundle for 2012-2019 27" iMacs with a Factory-Installed HDD or Fusion Drive, 1 TB 6G SSD, Drive Converter Bracket, in-line Digital Thermal Sensor Cable, Installation Tools :
How to Upgrade iMac Hard Drive or SSD 2012-2022: EveryMac.com
hard drive - iMac 27" late 2012 SSD upgrade - Ask Different
A list of successful iMac 27" (2012-2019) SSD upgrades | Page 39 | MacRumors Forums
Amazon.com: OWC 2.0TB HDD Upgrade Kit Compatible with All 2012-2019 27” iMac Models : Electronics
DIY Bundle - 2TB OWC 6G SSD and HDD Kit for 27-Inch iMac
Amazon.com: OWC SSD Upgrade Bundle for 2012-2019 21.5" iMacs, Mercury Electra 1.0TB 6G SSD, Express 2.5" USB 3.0 HDD Enclosure, Installation Tools and iMac Screen Adhesive Tape Set : Electronics
maxupgrades.com: Single SSD Drives kit for iMac 27 inch 2012 Models with SATA Blade SSD Module / Heatsink/ Power Cable and DATA Cables for [SSD + HDD] with iMac Adhesive LCD Tape
How to Upgrade the Main Drive in a 21.5-inch iMac 2012-2015 (iMac13,1 iMac14,1 iMac14,4 iMac16,1) - YouTube
Amazon.com: OWC 1TB Aura Pro X2 NVMe SSD Upgrade Kit Compatible with Select 27" and 21.5" iMac Models (Late 2013 - Current) : Electronics