NIOSH-approved for sites that expose workers to certain acid gases and particulates. Fits all North Safety Air-Purifying Respirators. P100 - 99.97% filter efficiency for protection particulates, including those that contain oil based aerosols. Acid Gas Protection - Helps protect against certain acid vapors. Fits North APR face pieces - No adapters needed. Fits directly onto North half masks and full face pieces. Proven to protect against these gasses and particulates: Formaldehyde, Chlorine, Hydrogen chloride, Sulfur dioxide, Hydrogen fluoride, Chlorine dioxide. Particulate (99.97% minimum filter efficiency). North offers an extensive line of gas and vapor cartridges and particulate filters to satisfy numerous industrial applications. All North cartridges and filters are approved with all North air-purifying half masks and full face piece respirators. One line of cartridges and filters will simplify your inventory. Air-Purifying Respirators with cartridges provide respiratory protection against gases and vapors by using sorbents to purify the inhaled air. Cartridges without filters do not remove dusts, fibers, and other particles.