COVID-19 Mask with Dechatlon Subea Snorkel and 3M particle filter

You can use 3M 5911 P1R or better 3M P3 particle filters with the SUBEA snorkel mask found in Decathlon.
It has a big valve to prevent moisturizing from breath the filters and bacteria deposition. The Air always flows in one direction, through filters, piston valve, your lung, out through subea mask valve.
Please read the print instructions,
the valve piston should be light as possible around 10g.
the adapter should be printed in contour to ensure good sealing performance and glued to the main housing so this way it can be detached anytime from the mask.

find old concept R1 step as well, it has a much smaller valve, if you want to test out the principle, or need adapter geometry for this mask

Print instructions

use G code, I used support only at the end of the housing in the area where the adapter comes, It was designed to be possible to 3d print easy