The IOGEAR USB 2.0 External DVI Graphics Card instantly adds an additional high resolution DVI display through your USB 2.0 port. Simply install the driver, plug the adapter into the USB 2.0 port and you're ready to go.Extend your desktop across both displays allowing you to increase your productivity like never before. While reading email on one display, open attachments on the other display. Expand spreadsheets across both monitors; in graphics programs you can increase your working area by putting all your pallets on the second display.IOGEAR's USB-DVI adapter is powered through the USB cable so no additional power supply is needed. By using USB there is no need to open the computer. Adding a second internal video card to a desktop can be complicated and impossible in some cases. With the IOGEAR USB 2.0 External DVI Graphics Card, just plug it in.