Protect family members and pets from harmful air pollutants with this pleated, long-life HEPA cartridge filter. The unit fits inside the dust compartment of any Hoover bagless upright vacuum cleaner equipped with the Twin Chamber System--use it in the Empower, WindTunnel, Savvy, and Anniversary bagless uprights. The HEPA filter traps 100-percent of dust mites and 99.8-percent of ragweed and common grass pollens. For best results, replace the filter every three to six months or as needed based upon usage. The replacement filter measures approximately 8 by 8 by 14-2/5 inches.