The j5create USB 3.1 to 4K HDMI Display Adapter JUA354 acts as an external video card for your MAC or PC. It allows you to add an additional monitor/display through your USB 3.1 port. No need to open up the computer to add an expensive video card: with the USB 3.1 to Dual HDMI Multi-Monitor Adapter you simply load the drivers: plug in the adapter to the USB port: then plug in the HDMI monitor cable into the adapter and you are ready. The USB 3.1 to Dual HDMI Multi-Monitor 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: great for spreadsheets. Mirroring mode is used to clone one screen onto another: ideal for presentations. With "Plug & Play" functionality between your computer and 2nd monitor or projector: you will be able to create a new visual environment in seconds.