Seagate Expansion portable drive, add-on storage for your PC The Seagate Expansion portable drive is compact and perfect for onthe-go. Instantly add more storage space to your PC or Mac and take large files with you when you travel. Setup is simple and straightforward; simply connect a single USB cable and you are ready to go. The drive is powered from the USB cable, so there is no need for an external power supply. Plus, it is automatically recognized by the Windows or Mac operating system, so there is no software to install and nothing to configure. Saving files is easy—simply drag-and-drop. Take advantage of the fast data transfer speeds with the USB 3.0 interface by connecting to a USB 3.0 port.