I wanted to upload this in case anyone needed a good starting point for Ring Sensor Gen 2 shells. 

The PLA printed shells are 1.5mm thick, so they are stiff and hard to break.

These larger and smaller sensors fit snugly within their respective shells, and it is important to note that when flipped upside-down, they will not fall.

This model is supposed to be built off of since doors and trim can vary - so a good idea would be to make a base/holder off of these shells to put on your door!

Let me know if you want me to change anything - Thanks!