I printed these models without any support.
Material Polylite ABS
Infill 13%
Layer 0.2
Update:
I'm a bit embarrassed to show Fusion360 file publicly because these were my first attempts at using Fusion360 :-) Now that I know a little more about how to properly design in Fusion360, I know how bad it was :-( But maybe someone find that useful as a start for future modifications - Please don't judge me too harshly ;-)
The author remixed this model.
I took idea Phil presented but I completely redesigned/redo that model from scratch. The main goal was to add container so you can put activated carbon you will get hepa and carbon filter