Amazon.com: OWC 32GB (2 x 16GB) PC19200 DDR4 2400MHz SO-DIMMs Memory Compatible with Mac Mini (Late 2018), 27" and 21.5" iMac (Mid 2017), and Compatible PCs (OWC2400DDR4S32P) : Everything Else
How to Upgrade/Install Memory in a 21.5-inch iMac (Mid 2017) iMac18,1 iMac18,2 - YouTube
Apple A Grade Desktop Computer 27-inch iMac A1419 2017 MNEA2LL/A 3.5 GHz Core i5 (I5-7600) 48GB RAM 4TB HDD Storage Mac OS Include Keyboard and Mouse - Walmart.com