Use with 3M™ Respirators 5000 Series or 3M™ Cartridge 6000 Series with 3M™ Adapter 502, 3M™ Facepieces 6000 Series or 3M™ Facepieces 7000 Series with bayonet filter holders. When properly fitted, use for a variety of applications including aluminum processing for concentrations up to 10 times the Permissible Exposure Limit (PEL) with half facepieces or 50 times PEL with full facepieces. Full facepieces must be quantitatively fit tested to claim assigned protection factor above 10 in negative pressure mode. Also offers nuisance level relief from other acid gases that are below the PEL. Nuisance level refers to concentrations not exceeding OSHA PEL or other applicable government occupational exposure limits, whichever is lower. Do not use for respiratory protection against acid gases or in environments that are immediately dangerous to life or health (IDLH).