WD  My Book Studio 500 GB USB 2.0/FireWire 400/800/eSATA Desktop External Hard Drive Plug-and-play setup for easy installation Automatically backs up important data, synchronizes files to keep them current Compatible with USB 2.0, FireWire 400 and 800, and eSATA Formatted for Mac OS X 10.4.8 or later, can be reformatted for Windows 2000, XP, and Vista Turns itself on and off with your computer and Safe Shutdown prevents the drive from being powered down until all your data has been written