2 Genuine Hoover WindTunnel Air, WindTunnel 3 Pro Bagless Upright Primary Washable Filters. This filter is located inside of the dust bin. Hoover recommends washing this filter every 30 days, and replacing it every 6 months. Save money with the 2 pack bundle, in addition to always having a clean, dry filter ready to use while you wait for the other to dry.