Review on Dulzod Dust Masks - Reusable Outdoor Sport Mask with Carbon Activated Filters for Dust Protection - Black Cloth Face Mask with Filter by Robert Arneson

The one-way valves of the mask were defective: air could both exit and enter through the valves. Therefore, the mask does not provide protection as an air filter. I highly recommend checking the valves before using the mask as an air filter. This problem occurred with each of the four masks purchased and each was from a different seller. By fitting a PM2.5 filter in the mask over the valves, the mask can be used as a 2.5 filter mask. Alternatively, you can attach a quarter-sized piece of plastic bag (food grade) to each valve. With each repair, the mask can be used as a 66% COVID air filter, but with the loss of the exhaust path provided by the valves. KN95 or N95 filters, which provide 95% filter isolation, can be similarly installed in place of PM2.5 filters. This can extend the life of 95 filters because when wearing it, hands touch the sports masks, not the filter.