CPU Fan for iMac 21.5" A1311 (Late 2009-Late 2011)
iMac 2009 to 2011 (A1311/A1312) Upgrade Guide – MacintoshMen
Amazon.com: Timetec 16GB KIT(2x8GB) Compatible for Apple DDR3 1333MHz PC3-10600 CL9 for Mac Book Pro (Early/Late 2011 13/15/17 inch), iMac(Mid 2010, Mid/Late 2011 21.5/27 inch), Mac Mini(Mid 2011) MAC RAM Upgrade :