OWC 8.0GB 2666MHz DDR4 PC4-21300 SO-DIMM 260 Pin Memory Upgrade, (OWC2666DDR4S08G), for 2018 Mac Mini (macmini18,1), 2019 27 inch iMac (iMac19,1) and PC laptops : Amazon.in: Computers & Accessories
iMac RAM Upgrade mixing different memory sticks: 27” iMac late 2013 - YouTube
Apple iMac 27-inch (Latest Slim Model) i5 12GB RAM 1TB HD OS X Yosemit | Laptop Workshop