CMS 16GB (4X4GB) DDR3 10600 1333MHZ Non ECC SODIMM Memory Ram Upgrade Compatible with Apple® iMac Core I3 3.06 21.5-Inch (Mid-2010) - A28 at Amazon.com
8GB -2x4GB Memory Ram Upgrade for 27" Apple iMac 11.3 Core i5 3.6GHz Mid 2010 | eBay
Install memory in an iMac - Apple Support
Apple A1311 iMac 21.5" Mid-2010 Core i3 4GB RAM 500GB HDD High Sierra | Chipped | 2nd Gen | Team Spares
Apple iMac 21.5 A1311 (MID 2010) spare parts in Cape Town South Africa
How to upgrade RAM / Memory on a 2010 iMac Core i3 i5 i7 (21.5in & 27in) - YouTube
Timetec 16GB KIT(2x8GB) Compatible for Apple DDR3 1067MHz / 1066MHz PC RAM for Mac Book (Mid 2010 13-inch), Mac Book Pro (Mid 2010 13-inch), iMac (Late 2009 27-inch), Mac Mini (Mid 2010)