A rain cover for the ashtray - so that it can simply stay where you need it in good weather.
As protection against being blown away, the thing has three locking lugs with which it can be locked. (I had to remove two of these lugs after printing because the lid was too hard to lock. One locking lugs serves the purpose just as well.)
[Fits on this ashtray](https://www.aldi-nord.de/angebote/angebote-mo-24-08/aschenbecher-set-1005094.article.html)