DATARAM 32GB Memory RAM Upgrade (2 x 16GB) DDR4 2400Mhz PC4-19200 CL17 SO DIMM Compatible with The Apple iMac Core i5 2.3 21.5-Inch (Mid-2017) 18, 1 at Amazon.com
OWC Tears Down iMac Retina 4K, Confirms Memory Is Soldered
Amazon.com: A-Tech 16GB (2x8GB) RAM for Apple iMac 2017 (27 inch Retina 5K & 21.5 inch Retina 4K) | DDR4 2400MHz SODIMM PC4-19200 1.2V 260-Pin SO-DIMM Memory Upgrade Kit: Office Products
Refurbished Apple iMac 18,2/i5-7500/8GB RAM/1TB SSD/21.5-inch 4K RD/AMD Pro 560+4GB/A (Mid - 2017) - Mac4sale