The Clickfree HD Transformer Cable adds Clickfree Automatic Backup to any external USB hard drive. Connect the Transformer Cable to your computers USB port, then connect any USB hard drive to the Transformer, then backup will start automatically. Made especially for those who want a simple backup solution, but already have a USB hard drive with free space. The Transformer will never over-write data already saved to the hard drive, and you can continue to use your USB hard drive as usual, but now it will also backup your computer whenever you connect it with the Transformer Cable. The Ultimate Backup Experience: With all Clickfree products, just connect to your computer's USB port, and Clickfree will automatically find, organize, and backup photos, videos, music, and hundreds of other file types. Clickfree eliminates the need to copy and paste files manually. Working right out of the box with no software to install or setup, it's truly automatic. Smart Backup - Clickfree will find and backup only files that are new or have changed since your last back up, making backup quick and efficient. You can backup multiple computers, Mac or PC. Smart View - Files are organized automatically, easy to browse and share. Clickfree organizes files on the backup automatically by computer name and category (Photos, Music, Spreadsheets, Presentations, Email, etc.). Smart Restore - Restore easily to a new computer even when upgrading to a new Windows version, or when transferring files from a PC to a Mac. Restore is also a great way to copy files or photos to another computer. You can restore everything back to original locations with one click, or if you want more control, you can choose the files, folders, or categories you want to restore. Requires a USB hard drive. Compatibility:- Windows XP, Vista, and Windows 7, Mac OS X 10.5 or later, with Intel Processors, 2 year warranty.