I've you're always interested in keeping you're passport safe and avoid damages, a protection is best.
This case can store an international passport and some other small documents, like boarding passes, …
It uses a rubber band to keep everything inside and allows to add an additional rubber band with handle to the front. This could be used as quick additional space for anything.

Dimensions:
Print settings:
Assembly:

First install the rubber band to the back and ensure it will be tight enough when placed around the front flaps. Two knots on the rubber band ends should be enough. They will slide into the holes on the sides of the bottom part pretty easy. Same attachment process for the front rubber band.
Then glue the front plate to the bottom part. Ensure they will be nice and flush on the glue pads.

Lastly attach the rubber band handle on the front band. I will snap, but a bit glue won't be wrong.
Uploaded newer version with several improvements (V11 files):
The author marked this model as their own original creation.