This small box is for the storage of a single trumpet mouthpiece.
I printed those with PETG and PLA.
The thread worked well for me with 0.4 and 0.6 mm nozzles and a layer high between 0.1 and 0.2mm.
UPDATE 19.02.2022
I updated both parts.
I added a hole on the bottom of the cup, so that there won't be a problem, if there is some moisture inside the mouthpiece. I also adjusted the inside a little bit, so that there is no sharp edge inside.
On the cover I added a rounding on the outer edge.
The author hasn't provided the model origin yet.