Apple iMac 27" A1312 MC813LL/A MC814LL/A Mid 2011 Series Intel Socket LGA1155 System Logic Motherboard 820-2828-A.
Apple Part Number: 820-2828-A
Compatible Part Numbers: 661-5948 661-5949 661-5950 31PINMB00J0
Compatible Models: Apple iMac 27" A1312 MC813LL/A MC814LL/A Mid 2011 Series
Please Note: This motherboard does NOT come with a CPU.