(4) Hoover WindTunnel Self Propelled 3 Layer Final Vacuum Filters, Bagless, Upright, Widepath, Empower, Foldaway, PowerMax Vacuum Cleaners, 40110006, 38766021, 38766-021, H-38766021 Part No # 40110006, 38766021, 38766-021, H-38766021