The JUA190 USB 2.0 Display Adapter acts as an external graphics adapter for your PC. It allows you to add an additional VGA monitor/display through your USB 2.0 port. There's no need to open your computer to add an expensive graphics card. With the USB 2.0 Display Adapter, you simply load the drivers, plug the adapter to the USB port, then plug in the VGA monitor cable into the adapter and you are ready. The adapter supports three viewing modes. Primary Mode allows you to have individual applications open on each monitor, vastly improving productivity. Extended Mode allows you to extend your desktop across multiple displays, which is great for spreadsheets. Mirroring Mode is used to clone one screen onto another, which is ideal for presentations.