These are genuine paper and cloth filter bags for various ducted vacuum machines. Most ducted vacuum systems take paper bags only eg. AstroVac, AussieVac, Valet, and Premier Clean. A few other brands such as Silent Master and CentralVac will need both paper and cloth bags for their filtration. Paper filter bags disposable, which are not designed to be re-usable. Reusing the bags for more than a year may cause the bags to break and dust to enter the motor. It is advisable to change your ducted vacuum bags twice a year to maintain healthy motor life. Please note that using non-genuine "brown-colour" ducted vacuum bags may shorten your motor life, as the material creates higher resistance (letting less airflow) than the original bags, causing the motor to overheat. Using non-genuine bags may also void your warranty.