I tried 2 designs off of Thingiverse, and found that the first design had the slots for the SD cards too tight and the second design had too little tolerance on the threads, so the top and bottom wouldn't go together.

Designed with tolerances in mind

Optimized for 0.16 mm layer height and a 0.4 mm nozzle

While designing this little container, I used increments of 0.16 on the Y axis and increments of 0.4 mm on the X and Z axis, to ensure a perfect slice with these 2 settings.