Designed for high filtration of common household allergens. Fits Hoover upright vacuums, including the WindTunnel uprights, that use \"Type Y\" or \"Type Z\" bags. Includes 3 bags per pack. Type Y Allergen filtration. Traps over 99% of dust and allergen matter down to 5 microns such as including household dust, dust mite debris, grass and ragweed pollen.