The P-A-1 replacement filter set is a proprietary circular threaded design that is lightweight, low profile and modular. The P-A-1 replaces the filters on the PARCIL DISTRIBUTION PD-100 full face respirator and T-60 half face respirator mask. Each filter cartridge is a dual-purpose organic vapor and particulate filter, classified as a "Combination Gas/Vapor and Particulate Filtering Cartridge." Activated charcoal is used to filter out organic vapors and the KN95 particulate filter is used to filter harmful microscopic particles. Our filters are ASTM tested to meet the same specifications as N95 ratings as per NIOSH regulations. The filters have a 3 plus year shelf life. The useable lifespan depends on the particulates and/or toxins in environment you use them in. They are designed to filter our many common chemicals found in cleaning compounds, alcohol, asphalt, mold, coal, detergents, disinfectants, fumes, hospital odors, industrial wastes, organic chemicals, poison gases, resins, viruses and many others. Chemicals filtered: dust, gasoline, smoke, carbon dioxide, ether, nitroalkane, nitrobenzene, carbon trichloride, nitrobenzene, chlorine benzene, acetone, anilines, carbon dioxide, carbon tetrachloride, chloroform, chloropicrin and many other pollutants. Useful applications include mold remediation, chemical production, fire inspection, epoxy resin use, mining, metallurgy, herbicides, pesticides, industrial production, paint application and smoke/toxic vapor. Color: White.