AMD Radeon HD 6970M 2GB graphics card for the iMac Intel, Alu 27".
This range suffered from a common GPU failure, which was later covered by a replacement programme with Apple. That programme is now over.
This listing is for a 'reballed' GPU, which is the only long term fix for the common GPU fault on these ranges
(the fault occurs when the lead free solder under the GPU cracks and loses connection, it is often not a component fault. so a 'reball', a process of replacing the solder under the chip with leaded solder, is the only sure way of repairing the board.)