661-7373 820-3302 Logic Board for iMac 2.7GHz 21.5″ MD095LL MD096LL ME699LL NB-4692W This is a replacement 2.7GHz logic board for the Late 2012 iMac 21.5" with 512MB VRAM. There are two variants of this product. A 2nd revision came out a few months after the first version adding Fusion Hard Drive support. Apple part number: 661-7373, 820-3588-A, 820-3302-A