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
Timetec 8GB KIT(2x4GB) Compatible for Apple DDR3 1067MHz / 1066MHz PC3-8500 CL7 for Mac Book, Mac Book Pro, iMac, Mac Mini (Late 2008, Early/Mid/Late 2009, Mid 2010) SODIMM Memory MAC RAM Upgrade
How to upgrade RAM / Memory on a 2010 iMac Core i3 i5 i7 (21.5in & 27in) - YouTube
Apple iMac 2010 21.5” Intel i5 3.60GHz 4GB RAM 2TB HD ATI 512 MB, Office, I Life | eBay
iMac RAM for Model 11.2 to 12.2 | DDR3-1066MHz | 8GB | MacMemory.com
Apple iMac 2010 8GB DDR3 1333MHz PC3-10600 204-Pin SoDIMM
OWC Performance Upgrades for iMac 2010
A-Tech 8GB RAM for Apple MacBook Pro (Early/Late 2011), iMac (Mid 2010 27 inch 4-Core, Mid 2011 21.5/27 inch), Mac Mini (Mid 2011) | DDR3 1333MHz PC3-10600 204-Pin SODIMM Memory Upgrade Module at Amazon.com