Summary

Update 2/5/19:

After several weeks of testing, it seems I need to increase the clip length to 200% in Cura (Uniform scaling turned OFF!) . This is because the clips tend to popped off.

I will update this later to see if this fixes my issue

I have nothing against a belt but they are a rather pain to use.

You need to tighten them
Need to loosen them to go to the bathroom

Thus I designed a simple clip that allows you to tighten your pants without needing to use a belt.

My design for jeans, I have not tested in on non-jeans.

Info

I used a 10% infill
I printed two for myself, I could print more if needed

Other

I suggest you sand the sides of the clip
I printed my clips in grey because thats the color I had, but if you print them the color of your pants, maybe people wont notice it
I see no reason to remove the clips from pants when the pants not in use.
There are 3 "slots" in the design, with the jeans, i was only able to use the outer two slots because jeans were hard to put into all 3 slots.
- This is the reason I use 2 clips, however I would guess if you use this clip on more flexable material, you should be able to use all 3 slots

I am thinking I will make a version for animals.