AIRx filters are compatible replacements for and designed and built to the same fit and performance specifications as the original filters that came with your vacuum cleaner. Replaces Filters in Shark NV500 Series canister vacuum cleaners Improves air quality Includes two (2) post motor HEPA filters, four (4) pre motor filter pads, and four (4) pre motor foam filters Replace the filter every 1-2 months Maintains performance of vacuum while reducing dust, pollen and other allergens in your home HEPA Filter Dimensions: 5-1/4" X 3-3/4" Foam Filter Dimensions - 3-1/2" Dia X 4-1/2" .