Snorkel Mask with P3R Filter for Doctors
The engineers first selected what masks to work with, choosing Decathlong and Sportisimo for their availability and low price. The key step was then to design the component which connects the snorkel with the filter (P3R filter, which offers both inward and outward protection, was chosen, but cheaper HEPA could also be considered).
The main advantage of this solution is that the mask covers the whole face so the infection should have no chance to get to the body via airways or nasal mucosa. The main disadvantage is that huge numbers of snorkel masks are being bought for medical use – no way that anyone can buy snorkel masks for actual snorkeling anytime soon!
The production costs are about 20 EUR. If you want to make these masks yourself, see the authors' documentation (https://covid19cz.implayo.cz) just in Czech so far, let us know if you need translation).
The designers do not hide their sources of inspiration: Easy Covid19 mask by Isinnova and Easybreath gas mask adapter.