Air purifying respirators with cartridges provide respiratory protection against gases and vapors by using sorbents to purify the inhaled air. The combo P100 particulate filter provides protection against aerosols by removing dusts, mists, fumes, fibers and other particulates; 99.97% minimum filter efficiency. 3M offers wide selection of combo cartridges to provide respiratory protection against a range of industrial air contaminants. The outer casings are made from a durable, lightweight material, and color coded for quick and easy identification. The combo cartridges are approved for use with both 6000/7000 series half mask and full facepiece respirators. All cartridges are NIOSH approved, meet 42 CFR 84 requirements, when used with 3M air-purifying respirators. 2 cartridges per package. 30 packages per case. Sold by the package.