Designed specifically for the HEPA 700, these pre-filters and HEPA primary filter ensure the highest air filtration efficiency. With its standard 2-inch pre-filter and primary HEPA filter media, the HEPA 700 removes dust, contaminants and other particulates and passes the stringent DOP air filtration tests often required. The optional activated carbon filter with a 1-inch pre-filter and HEPA filter will remove odors, fumes and smoke - especially helpful in wildfire-prone areas.