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)
Install memory in an iMac - Apple Support
APPLE IMAC 2010, ALL-IN-ONE, 21″ inch Full HD , CORE 2 DUO, 2.26GHZ, R – Montag Store
How to Upgrade Memory in a 21.5-inch or 27-inch iMac (Mid 2010) - YouTube