610-0026 069-3692 922-9120 Fan, Optical Drive - 21.5 inch iMac Late 2009 A1311 3.06-3.33GHz NB-3179W This is a replacement optical drive fan for the 21.5-inch iMac. If you are having overheating issues or loud noises around your optical drive, you may need this replaced. Apple part number: 922-9120, 610-0026 069-3692