Type: External Features: Dimensions: 5" x 3.3" x 0.7" Weight: 0.56 lbs. Precision aluminum enclosure FireWire 800 ports WD Security WD Drive Utilities Formatted for Mac No power adapter required Compatible with Apple Time Machine Compatibility: Formatted HFS+ Journaled for Mac OS X Leopard, Snow Leopard, Lion. Can be reformatted for Windows XP, Windows Vista, Windows 7