Use with Respirators 5000 Series or Cartridge 6000 Series with Adapter 502, or Half and Full Facepieces 6000, 7000 and FF-400 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. Refer to specific provincial regulation for appropriate assigned protection factors for full face respirators. 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).