Nutone 391 Replacement Bags for Central Vac, Set of 3 Six Gallon Bags Nullify Imported Deep cleaning is no longer a chore with NuTones tight-seal vacuum bags. The bags capture and tightly seal dirt, dust and allergen particles away with reliable efficiency to make your home a cleaner, healthier place for your family to live. 2-ply electro-statically charged filter media captures particles down to .10 micron at 85% efficiency, ensuring a clean and healthy environment for your family Suggested replacement about twice a year allows for maximum performance and efficiency. For use with CV 350, CV352, CV353, CV450, CV653 and CV750