car microphone cover

A friend of mine could not use the microphone integrated in his Renault Clio 4, so he removed the cover, and rotated the microphone downwards.
After that mod the microphone was working fine, but needed some protection because it was protruding from the ceiling inside the car.
I've quickly sketched this small cover in openscad, I didn't even have a caliper at hand, I've used a simple ruler =_)