Triangle key for some plastic door - 10mm triangle side, 16mm circle diameter, at least 8mm depth.
Remix - I took the top handle off and slaped it on the cylinder with the triangle cut out. Since tinker card does not center a triangle properly I've eye-balled it - but hey, it works!
https://www.tinkercad.com/things/i17nC7ongPY-triangle-key
No supports. I printed in PETG to withstand our heat in the car.
The author remixed this model.