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 RAM in the (Mid 2017) 5K iMac and save up to ~$900 [Video] - 9to5Mac
Timetec Kit de 32GB (2x16GB) Compatible para Apple 2017 iMac (27 Pulgadas con Retina 5K, 21.5 Pulgadas) DDR4 2400MHz PC4-19200 SODIMM Mac RAM Upgrade para iMac18.1/iMac18.2/iMac18,3 : Amazon.es: Informática
How to upgrade RAM in the (Mid 2017) 5K iMac and save up to ~$900 [Video] - 9to5Mac
Reemplazo de RAM del iMac Intel 21.5" Retina 4K Display (2017) - Guía de reparación iFixit
OWC 64GB (4 x 16GB) PC19200 DDR4 2400MHz SO-DIMMs Memory Compatible with 27" iMac (Mid 2017), and Compatible PCs (OWC2400DDR4S64S)
Upgrade your iMac 27'' 2017 RAM with MrMemory review - Wim Arys
Adamanta 16GB (1x16GB) Memory Upgrade Compatible for 2017 Apple iMac 21.5" Retina 4K Display and Non-Retina Display DDR4 2400Mhz PC4-19200 SODIMM 2Rx8 CL17 1.2v Dual Rank RAM DRAM at Amazon.com