What really counts for max effectiveness is the electrostatically-charged HEPA cloth, but even woven cotton is better than just breathing in the invisible exhaled infected floating CV specks you can't see.
What really counts for max effectiveness is the electrostatically-charged HEPA cloth, but even woven cotton is better than just breathing in the invisible exhaled infected floating CV specks you can't see.
Would double sided strips of Velcro work as retainer straps?