This highly efficient filter is an excellent upgrade to your existing FM-230 or DC-500H dust extractor. Pleated cartridge filters are far more efficient than even needlefelt filter bags.
This one is manufacturer rated at 1 micron. It will also suit many other brands of 1 hp dust extractors with a drum diameter of 375mm and drum height (excluding handle) of 546mm. The unit is cleaned by rotating the handles located on the top of the filter several times. Doing so rotates a rubber beater inside that removes settled dust from the pleats, helping them to fall into the collection bag.
The filter unit needs to be used in conjunction with plastic collection bags in place of cloth bags. Collection bags are available in packs of ten in the relevant sizes for each machine. Pleated cartridges not only provide vastly enhanced micron filtration, the pleating increases the surface area by up to 700%. This increased surface area in turn also increases the CFM rate creating more suction from the impeller unit.