Introducing the Single Micron 21 in. x 31 in. Dust Collector Filter Bag by POWERTEC. This industry leading 1-micron dust collector filter bag was manufactured to capture up to 99% of fine dust particles created by various types of sanding applications, table saws and other woodworking projects - without a reduction of airflow. This not only improves the visibility of your working area, but the air quality of your shop as well. //Top Design // This dust filter bag is constructed of ultra-thick material. It possesses high sustainability. (Please note: This is ONLY to be utilized as a Top Filter Bag for your Dust Collector.) The POWERTEC Dust Filter Bag is designed to optimize your dust collection system and maintain clean air in your work environment. This bag is 99 percent efficient in capturing fine dust particles from sanding and other wood-working operations. It is made of polyester felt with a singed finish. Felt features high breathability and fine particle separation. Singed felt allows a very thin layer of fine dust particles to collect and build on the surface of the bag. 【Compatibility】Harbor Freight, Shop Fox, Delta, WEN, JET, Grizzly, and many others.