When I travel, I like to have my Hum toothbrush with me, but using the original case means you have to take the brush head off to put it away. So this 3D print allows you to store the toothbrush with the brush head attached.

I used PLA on my Prusa printer with .20mm detail printing and the case top fits fairly snug on the case bottom. Taking it on and off a few times makes it easier to slide. You can sand the bottom a bit if necessary. The OpenSCAD files are included if you want to adjust the size there.