This is a screen expansion box that allows one D-sub/DVI output to be displayed on three monitors. DVI to HDMI conversion should be possible with an adapter, but since I haven't tested it, HDMI display is not guaranteed. Since it can recognize three monitors as one, it's suitable for creating a wide screen by connecting standard 16:9 monitors, or when you need a wide screen with projectors for projection mapping, or for advertising monitors. The screen size is limited by the PC's graphics capabilities. If your current system uses this, it's difficult and expensive to obtain (70,000 yen on Amazon), so you might consider getting a spare one at this opportunity. Operation has been confirmed, so no claims or returns are accepted. Matrox TripleHead2Go Digital Edition Brand: MATROX