I was searching a light-tight vent for our experimental setup, because a system manufacture added two powerful inlet fans for a cooling, but no any outlets...
I did not like the round vents I have found here on site, so have quickly designed my own "square" version of it. 4x 6mm bolts for attachment, spaced in 100x100mm square.

It dims a light quite efficiently.

The best filament would be something, clearly, black and scattering, not glossy.

Prusa

MINI

No

No

0,2

15