OWC DIY Drive Upgrade/Install Kits for Apple iMac Models
Amazon.com: ACASIS USB C 3.2 SSD Enclosure for Apple Flash SSDs 12+16 PIN MacBook Pro,MacBook Air, Mac Pro, iMac from 2013 to 2017 Portable Storage Enclosure Compatible with M.2 Nvme SSD with
SATA Blade SSD Module - Dual SSD Drive Kit for iMac 27 Inch 2012 Model - Walmart.com
OWC DIY Drive Upgrade/Install Kits for Apple iMac Models
SSD soldered: Apple kills off the 27 inch iMac's storage upgradability - NotebookCheck.net News