This HDD SATA Data Cable will work in the iMac models listed below:
iMac (21.5-inch, Mid 2011)
Model No: A1311
Model Identifier: iMac12,1
Apple Order No: MC309LL/A (2.5 GHz), MC812LL/A (2.7 GHz)
EMC: 2428
iMac (21.5-inch, Late 2011)
Model No: A1311
Model Identifier: iMac12,1
Apple Order No: MC978LL/A
EMC: 2496