I carry my Husky utility knife with me all time. If I don't forget it somewhere, which happened several times a week. So I used retractable badge holder to keep it on leash. But the badge holder is kind of flimsy, its clip is too small for my belt... So I designed my own belt holder.
It consists of two parts:
BadgeHolder_inner.stl is supposed to go on the belt. It has closed loop for standard 40 mm belt.
BadgeHolder_outer.stl holds the retractable holder itself and it's screwed on the inner part.
The print quality might be better if I would print the outer part the other way with support in hole. But it's good enough as is for me.