Hoover 40110006 Final Filter 2 Pack Fits inside the filter door of WindTunnel Self Propelled uprights and WindTunnel Bagless uprights with the Allergen Filtration System including U57009RM, U5720950, U5720960, U5725900, U5725960, U5750906, U5750911, U5752900, U5753900, U5753950, U5753960, U5753980, U5760900, U5760910, U5768900, U5786900, U6471900, U66009RM, U6607900, U6616900, U6617960, U6618900, U6630900, U6632900, U6634900, U6637900, U6637960, UH40020, UH40065, UH40115CA, UH40125, UH60000. Includes 2 filters per pack. Originally produced with green, yellow and white layers, now comes in just white. Change every 3 to 6 months.