Cetus Spool holder stopper

The spools kept falling off of my cetus spool holder. I generally like the spool holder, enough that I wasn't going to print a whole new one, so I printed this, that fits over the holder and stops the spool from falling. A little loose-fitting, but as long as you still have the black plastic cap to hold it in place, it works.

EDIT: I've made a second version, tighter-fitting and smaller. It no longer wiggles around or needs the cap to hold it in place, and since it's smaller it doesn't need to be removed for the smaller-holed spools (like AMZ3D) to fit over it anymore.