This is a mounting platform and sign bracket for the Avro Lancaster kit card by Estebene available at https://www.thingiverse.com/thing:4651894.
I printed the save plastic sprue based model. That is how the card frames should be sized. Just firm enough to hold it all together, and not the size required for mold injecting. Assembly was easy.
This is the first plane I have mounted on the new Horizontal Pivot platform. The frame had no signage so I used the standard custom print one is provided. I changed colors when the layers go to the top letters.
These parts are designed to attach to a 3UDC pivot arm so that you can present this model anyplace you have a 3UDC socket.
You can find the Kit Card Tree library of mounting hardware and instructions at https://www.printables.com/prints/126495
Collection of known Kit Card Tree platforms https://www.thingiverse.com/alwaystinkering/collections/kit-card-tree-platform-collection