These filters and cartridges are compatible with Honeywell North 5400, 5500, 7600, and 7700 reusable respirators. Particulate filters and vapor cartridges are NIOSH-rated and installed in reusable half-mask or full-face respirators to filter out airborne contaminants. They are selected based on the environment and type of respiratory hazards that need to be filtered. They can be changed out when they become dirty or when the type of contaminant changes. Filters and cartridges are compatible with a specific brand and mask model.