I broke this piece of the warning triangle compartment in the rear door of my Passat 3C (year 2009) by closing it too hard.
I have designed this just like the original and after 3 years I have not broken it again. It's true that I've not checked again if it holds the closure with the triangles in place. At least I don't have the compartiment door free and I keep the triangles with the spare wheel.
I think this is the OEM original VW reference: 3C9860285A9B9
I hope it will be useful to you
It is recommended to use PETG or ABS
The author hasn't provided the model origin yet.