Adamanta 64GB (2x32GB) Memory Upgrade for 2020 Apple iMac 27" w/Retina 5K Display, 2019 Apple iMac 27" w/Retina 5K Display, 2018 Apple Mac Mini DDR4 2666Mhz PC4-21300 SODIMM 2Rx8 CL19 1.2v DRAM
How do you install RAM in your iMac? - Coolblue - anything for a smile
How to Install Ram on the 2019 27 inch iMac and which Ram to Buy? - YouTube