This box holds filament sample cards that are 80 mm x 35 mm x 2.2 mm. I use 80x35x2 filament cards but like the extra room to be able to more easily add and remove the sample cards.

I included both a 50 card holder and 4 card holder so can print smaller sample box first if want to test sizing.

Here are the filament cards that work with this box. Filament Sample Card by sage117 - MakerWorld

I created a 40 card holder too that will work on A1 Mini with smaller plate too. Filament Sample Box - 40 by sage117 - MakerWorld

This box was created using SCAD files provided by Filament Swatches Box - Customizable Remixed by George GxG - MakerWorld. Go give them a boost if you enjoy this as I have.