Timetec 64GB KIT (4x16GB) Compatible for Apple 2017 iMac (27-inch w/Retina 5K Display) DDR4 2400MHz PC4-19200 1Rx8 CL17 1.2V Non-ECC Non-Parity Unbuffered SODIMM Memory MAC RAM Upgrade for iMac 18,3 at Amazon.com
Apple iMac 27-Inch with 5K Display Review (2017): Serious Power | Tom's Guide
Apple A Grade Desktop Computer 27-inch iMac A1419 2017 MNED2LL/A 4.2 GHz Core i7 (I7-7700K) 24GB RAM 512 GB SSD Storage Mac OS Include Keyboard and Mouse - Walmart.com
Amazon.com: Mid 2017 Apple iMac with 3.0GHz Quad Core i5 (21.5 inch Retina 4K, 16GB RAM 256GB SSD) (Renewed) : Electronics
Configure your own 27-inch Apple iMac (2017) at OWC