Reduce exposure to: smoke, acrid air, dust, pollution, fragrances, diesel fumes, mold and other particles. Effective for poor air quality indoors or on airplanes. A porous, lightweight, washable shell holds and seals a disposable carbon filter. Mask fits in a pocket. The adjustable ear loops allow for a personal fit and long wearing comfort, even with eye glasses, goggles or a helmet. Replace filter when breathing becomes difficult or odor comes through even after adjusting nose wire. How long a filter lasts depends upon your sensitivities and environment. You can talk and be heard while wearing these masks.