AeraMax SV Combo Filter - 2 pk - One Filter Pack, Three Functions: Combined H13 True HEPA and Carbon Filter plus separate pre-filter filter to capture larger particulate to help extend life of subsequent filters - Reusable Pre-Filter: Pre-filters are washable and can be cleaned as needed - H13 True HEPA Filtration: Captures up to 99.95% of particles as small as 0.1 microns, including allergens, pollen, dust, pet dander and smoke - Long-Lasting Performance: Two-year estimated filter life (depending on usage conditions) - 2 Sets Per Pack: Includes 2 Hybrid + Carbon combo filters and 2 pre-filters (two sets of filters are required for optimal operation)