Filtrete 3M Hoover Style Y Synthetic Vacuum Bag (Set of 10) 3M Filtrate vacuum bags are guaranteed to be free from defects in material and workmanship Synthetic vacuum bags expand as you clean allowing air to flow easily through the multilayer construction, trapping more dust and fine particles Replaces Hoover part number 4010100Y Replace bag every 30 to 60 days for optimum performance Fits all Hoover Windtunnel Upright Vacuums