There is wide wariety of membrane boxes made in China. They are well made, cheap, very helpfull in presentation collectible items like meteorite or mineral slices, stamps, coins etc.

One thing that I dont like is the external stands. Walls of boxs are angled so they cant stand itself. To each box You need extra stand. But they are not very good designed, take alot of space and offer only 90 deegrees andgle.

I designed four different versions (angles) 90, 95, 100 and 105 deegrees. 100 deegrees version is the best I think.
Front of stand is flat so You can print and put there specimen label. Thats very importand if You dont use labels like mine, inside box. Normally there is no enough space on edges of boxes to put any label becouse its only 7mm wide. You can use cheap thermal printer with 12mm tape.

Design is free for private use. Each 3D printer will print with different accuracy so I added Fussion360 original design. You can correct dimensions so the box fit into the stand perfectly. I added +0.2mm so the stands fit with small resistance.

I use Cura slicer and CR6-SE printer with PLA filament. Around 45min print time.
4 walls, 3 top bottom layers, 20% infill.

Enjoy