Last October, I described the 13" S1 secondary monitor from Sibolan ($200). You plug in an HDMI cable (for video and audio) and a USB cable (for power), and so have a second monitor for a laptop computer. See my original review here: https://www.worldcadaccess.com/blog// /
It's been nearly a half-year since, and so I thought I'd follow up.
In brief, I don't use it much. For me, it is useful only when typesetting with InDesign on my laptop, because I have an entire screenfull of palettes that need to occupy a second screen. And typesetting does not happen very often with my 13" laptop; a desktop computer with 23" and 18" monitors is preferable.
So, the S1 spends most of its time in its neoprene carrying case. On my most recent trip to Europe, I took it along and didn't use it once.
Afterwards, I noticed that it suffered from two largish reddish areas, which I think is where it might have been bumped during travel. If I were to take it along in the future, I would cut a thin sheet of plywood to size, to protect the screen from further damage.
A computer reseller did write to let me know that this monitor was the kind his customer was looking for.