D20 Countdown Dice Holder (Screw top)

The original countdown die by kittka is awesome - I initially shrunk it down and remixed it for different magnets (not shared, as I used an ugly mix of magnets I had on hand). A friend's puppy chewed on that, so I was a little more cautious about magnets for the replacement. [Editor's note: Alfred, you got lucky that you didn't eat magnets, even baby ones.]

Update: 2019/9/21
Added a remix under "D20 Dice Holder (Screw top, non-countdown)" - https://www.thingiverse.com/thing:3871911 for those