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
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
Timetec 16GB KIT(2x8GB) Compatible for Apple 2017 iMac (27-inch w/Retina 5K, 21.5-inch w/Retina 4K / Non-Retina 4K) DDR4 2400MHz PC4-19200 SODIMM MAC RAM Upgrade for iMac 18,1 / iMac 18,2 / iMac
Apple iMac 27 Inch 5K 3.5 GHz Core i5 1TB Fusion 64GB RAM 4GB GFX 2017 – Quality Macs
Install memory in an iMac - Apple Support
Amazon.com: 2017 Apple iMac with Retina 5K Display (27-inch, 8GB RAM, 512GB SSD Storage) (Renewed) : Electronics
A-Tech 64GB (4x16GB) RAM for Apple iMac 2017 27 inch Retina 5K | DDR4 2400MHz SODIMM PC4-19200 2Rx8 1.2V 260-Pin SO-DIMM Memory Upgrade Kit at Amazon.com