The JUA315 USB 3.0 VGA SLIM Display Adapter acts as an external video card for your Mac or PC. It allows you to add an additional VGA monitor/display through your USB 3.0 port. There is no need to open your computer to add an expensive video card. With the USB 3.0 VGA SLIM Display Adapter you can simply load the drivers, plug in the adapter to the USB port, then plug 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. With plug-and-play functionality between your computer and second monitor or projector, you will be able to create a new visual environment in seconds.