Designed to fit one's facial contour, the lightweight, flexible RZ Reusable Air Filtration Mask consists of a four-way-stretching neoprene or a moisture-wicking mesh exterior (depending on model); an activated-charcoal-filter interior, and left/right screened breathing valves-all of which are hand-washable. The mask filters out over 99% of the pollen, dust, allergens, diesel particulate matter, and other solid things that don't belong in the lungs or nasal passages (manufacturer's claim). The mesh model is recommended for heavy-dust-exposure situations (e.g., grain bin cleaning, livestock/grain handling, off-road travel, construction/demolition); the neoprene model for lighter-dust, allergen, pollution, odor, and/or cold weather protection.