Specifications

Left Bracket Right Bracket
Hard Drive Replacement
If installing a replacement hard drive, transfer the hard drive brackets onto the new drive. The brackets install only one way. Be sure to orient them
correctly.
Be careful not to pinch the cables under the Hard Drive Cradle assembly.
Wi-Fi/Bluetooth Antennas
iMac (21.5-inch, Late 2012) has four (4) Wi-Fi/Bluetooth antennas. Three of which are removable.
The fourth resides inside the Apple logo in the rear housing assembly. It can only be replaced by replacing the rear housing.