The Pentek BP-420-1 Filter Bag provides higher productivity with faster bag "change-outs." The bags are manufactured from felt because it can take on a heavy load of solids, in comparison to similar mesh fabrics. The manufacturing process involves multiple steps: layering together the felt material on a screen for support, then finishing it with a glaze for a secure bond. This is a product that can certainly hold its own as it filters dirt and debris.