I couldn’t find an AirTag holder to meet my needs, so I designed this.

I drew inspiration from the screw lock carabiner from luvem studios for the mechanism, but created the holder from scratch in Onshape.

https://www.printables.com/model/95972-screw-lock-carabiner

The hinge pin is a tight fit and may need to be adjusted depending on the tolerances of your printer. I made it slightly long so the excess can be trimmed when the pin is pushed home far enough.

works well at layer heights of 0.2mm or finer.