Review on 4K HDMI Emulator - High Resolution Virtual Display Plug, New Generation Headless Adapter for 3840x2160@60Hz Support, 1080@120Hz DVI EDID Simulation (Single) by Anthony West

These little gems allowed my Headless Mac Mini to run at a better resolution than the operating system would allow without a monitor attached. This is especially useful on newer Mac OS operating systems as Apple continues to remove headless output resolution options. Please note that if your source video system does not support this resolution, you will NOT get 4K resolution. You'll likely get 1080p, which is what I got on my two older minis, while we got 4K output on the slightly newer mini I tried. They are very economical compared to some other video adapters that are offered to improve the output resolution in this situation.