Adamanta 16GB (2x8GB) Memory Upgrade Compatible for 2017 Apple iMac 27"/21.5" Retina 5K/4K or Non-Retina Display DDR4 2400MHz PC4-19200 SODIMM 1Rx8 CL17 1.2v Single Rank RAM DRAM at Amazon.com
Apple iMac with Retina 5K Display (2017) review | Digital Trends
Restored Apple 27-Inch iMac Pro with Retina 5K Display (Late 2017) MQ2Y2LL/A, 3.2GHz Intel Xeon W, 32GB RAM macOS, 1TB SSD, - Space Gray (Refurbished) - Walmart.com
Apple iMac (27-inch, 2017) review: Apple doesn't mess with success - CNET
NEMIX RAM 64GB (4X16GB) SODIMM Memory Upgrade Kit DDR4 2400MHz PC4-19200 Compatible with Apple iMac