Type-Y HEPA bags trap 99.97 percent of dust & pollens down to 0.3 microns for cleaner air in your office. Easy-to-install design goes on & removes quickly for time-saving replacement. Disposable material allows you to conveniently discard filled bags for time-saving replacement. Bags are designed for Hoover upright vacuum cleaners, including the WindTunnel uprights, that use type Y bags.