The POWERTEC Dust Filter Bag is designed to optimize your dust collection system and maintain clean air in your work environment. This bag is an 99 percent efficient for capturing fine dust particles from sanding and other wood-working operations. The POWERTEC Dust Filter Bag is made of polyester felt with a singed finish. Felts features high breathability and fine particle separation. Singed felt allows a very thin layer of fine dust particles to collect and built on the surface of the bag.