The JUH450 USB 3.0 HDMI & 3-Port HUB acts as an external graphics card for your Mac or PC. It allows you to add an additional display and 3 USB 3.0 ports. With this multi-adapter, there is no need to open your computer to add an expensive graphics card; you simply load the drivers, plug in the adapter to the USB port, then plug the HDMI monitor cable into the adapter and you are ready. It supports three viewing modes: primary, extended, and mirror modes. 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.