I designed this to hold my large Dell Windows tablet for live streaming but it will hold any medium to large tablet from 130mm (5 1/8") to infinite height and a maximum of 18mm deep. The reason it has infinite height is because the top and bottom need to be joined by a threaded rod or long bolt that can be any length (a long toggle bolt would work and is cheap). The bottom has a dovetail and the top has a hole for a ¼" -20 insert if you want to mount a microphone or light or other. They are otherwise basically symmetrical so either could be used on top or bottom as well as mismatched for whatever you need. (My tablet has a slight taper on the back so the bottom slot is actually a tiny bit smaller but it is negligible)
I printed mine in TPU95A using 4 walls and medium infill for a softer feel but still plenty stiff enough for use. It is oversized and overengineered for this reason.
I included a picture of how I printed it. Doing it on it's side makes the layer lines perpendicular to the forces involved. It just needs a little support under the one angle and the one side of the dovetail (which is not shown in the picture). Everything else should print without support.
I have also included 2 slightly different tops. One is a bit taller for extra reinforcement for flexible plastic. The other is just flat on top.
The author hasn't provided the model origin yet.