this adapter fits my Leifheit Regulus Vacuum and connects to GlennovitS3D's Drill Dust Collector. You can get the actual Drill Dust Collector over there.
The Leifheit Regulus Adapter shape MUST be designed to infuriate 3rd party adapter makers. It's roughly oval shaped, but top and bottom have different radii and measuring all of this as well as finding a solution using bézier curves turned out to be a real multi hour challenge!
You can download a nozzle model fitting the vacuum for remixing here
In the end, I designed an adapter for the vacuum, which you can now download to make your own remixes for the thing. (CC-BY-SA means, please mention me if you use it in your designs and share it as freely as I did. Unless you are GlennovitS3D, then I just ask for the attribution)
The author marked this model as their own original creation.