This modular system is meant to build an outdoor water filter.
Depending on the filter material you have on hand, you can add or remove filter stages.
I also made different outlet-modules:
I´d highly recommend testing a small amount of water and boiling it after filtering before you drink the water that comes out of the filter system!
Edit Oct 23rd 2022:
Tested the filter in the field. As you can see on the pictures the muddy water came out pretty clear with a few pieces of charcoal. In the top stage I put gravel, next sand, next moss and at the bottom activated charcoal. After that I boiled the water and made some delicious lentil soup ;-)
The author marked this model as their own original creation.