Spare part for broken Gardena hose adapters. You need three of these Things inside the connector. I have neither printed no used this yet, so the Thing is still under construction until tested.

I have found the outer ring for the lock mechanism here:
https://www.thingiverse.com/thing:4083778

[Update]: I have tested the Things last weekend and they work fine! See photos!

I have simply scanned the original part and redrawn the outlines of the jpg in Onshape.