A-Tech 32GB (4x8GB) RAM for Apple iMac (Mid 2010 27 inch 4-Core, Mid 2011 21.5/27 inch) | DDR3 1333MHz PC3-10600 204-Pin SODIMM Memory Upgrade Kit at Amazon.com
iMac A1311 21.5” Core i3 3.06GHz 4GB RAM 250GB HDD HD 4670M High Sierra FHD – I.E.T. INDUSTRIAL ANTONIO PRIETO – SINCELEJO, SUCRE
Install memory in an iMac - Apple Support
Apple iMac 21.5" Intel Core i3 4GB RAM 500GB HDD A1311 w/Wireless KB & Mouse * | eBay
How to Upgrade iMac RAM (21.5" and 27" Aluminum): EveryMac.com
Memory Upgrades for Apple iMac 2011 Up to 32GB
Restored Apple iMac 21.5" Desktop i5 2.5GHz 4GB Ram 500GB HD High Sierra A1311 - MC309LL/A (Refurbished) - Walmart.com
Apple iMac A1311 21.5" (May, 2011) 20GB DDR3 RAM i5 2nd Gen CPU 512 GB SSD | eBay
Apple iMac 21.5" A1311 -i3 2.5GHz 4GB Ram 250GB MacOS High Sierra (GRADE B) | eBay
A-Tech for Apple 8GB Kit 2 x 4GB PC3-10600 Mac Mini iMac MacBook Pro Mid 2010 Late 2011 A1286 MD311LL/A A1297 MC511LL/A A1312 MC309LL/A A1311 MC812LL/A MC813LL/A MC814LL/A MC815LL/A A1347 Memory RAM
CMS 32GB (4X8GB) DDR3 10600 1333MHZ Non ECC SODIMM Memory Ram Upgrade Compatible with Apple®½ iMac 21.5" Intel Core I7 2.8Ghz (A1311) - C12 at Amazon.com