The MSA (Mine Safety Appliances) Safety Works Harmful Dust Respirator with exhalation valve features a patented nose bridge that contours to the facial dimensions of a wide population of users. The low profile valve assists with easier breathing and helps reduce heat and humidity. Meets NIOSH (National Institute for Occupational Safety and Health) 42 CFR 84 respirator certification regulations. The mask's dual elastic straps help keep it positioned properly on the face. Latex-free and hypo-allergenic.