Genuine Hunter H-PF600 replacement pre-filters. Fits Hunter air purifier models HP600, HP600BL, HP600WH, HP600GR. Coconut carbon pre-filter neutralizes household odors from cooking, cleaning, smoking and pets. Also captures larger particles before reaching HEPA filter, extending life of the HEPA filter. Recommended to replace pre-filter every 3 months for maximum efficiency, or more often depending on air quality and environmental factors. Package contains (2) replacement pre-filters.