Internal 500GB 3.5" Western Digital 7,200rpm hard drive mechanism with SATA (Serial ATA) interface.
This drive is compatible with any machine capable of housing a 3.5" SATA drive, but has also been tested to be working with the Aluminium iMac ranges 2009 and 2010 (21.5"/27").
(Please note, you will need to use the hard drive thermal sensor cable from your old drive to ensure the fans spin at the correct RPM speed. If you did not have a Western Digital drive fitted previously you will need to purchase the WD Thermal Sensor Cable for your corresponding iMac range, as every manufacturer had a different connection type)