WD 2TB Black My Passport for Mac Portable  External Hard Drive  - USB 3.0  - WDBCGL0020BSL-NESN Secure portable storage with up to 2 TB capacity Optional 256-bit AES hardware encryption Compatible with Apple Time Machine Stylish design complements your creative style USB 3.0 connectivity Formatted for Mac OS X, reformatting required for Windows 3-year limited warranty