Face Mask with valves

thingiverse

Based on https://www.thingiverse.com/thing:4228729 I added two valves for inhaling and exhaling. The valve can be made from thin polyethylene or, better still, rubber by screwing it onto a small screw. To fit the edges of the valves tightly, heat a flat surface such as a ruler until they melt into a perfect plane. The edges of the mask can be made less sharp and rubbing if you put insulation on them like molding. It must be cut lengthwise and the wires removed. As filters, it is better to use HEPA fabric. It can be taken from vacuum cleaner filters. Three layers are quite easy to breathe in. I also lengthened the mask a bit so that it wasn't too crowded.