Apple iMac 21.5" Mid 2011 Intel Core i5 2.7 GHz 1TB SATA Disk 4GB RAM HighSierra | eBay
CMS 16GB (2X8GB) DDR3 10600 1333MHZ NON ECC SODIMM Memory Ram Compatible with Apple Imac "Core I5" 3.1 27-Inch (Mid-2011) - A13 - Walmart.com
32.0GB OWC Memory Upgrade Kit For 2010-2011 Apple iMac
Timetec 32GB KIT(4x8GB) Compatible for Apple DDR3L 1600MHz PC3L-12800 CL11 for iMac (Mid 2011, Late 2012, Late 2013, Late 2014 Retina 5K, Mid 2015 Retina 5K) SODIMM Memory Module MAC RAM Upgrade at Amazon.com