The 3 Micron Filter Cartridge is a cartridge style filter with a particulate rating of 3 microns and can be installed for all general-heavy duty vacuuming applications where water is not present. This cartridge filter will remove most dust & debris from exhausted air and is only a slight step down from a genuine HEPA grade cartridge filter. The 3 Micron Filter Cartridge can be continuously used for many years as it is a cleanable accessory. It is possible to use KP700-20 (Models KP701,02,03) or KP704-B38 (Model KP704) “FILTER CLOTH HAT” in conjunction with this cartridge filter for additional debris filtration requirements. NOTE: A VACUUM FILTER ONLY WORKS WHEN IT IS CLEAN! IT IS RECOMMENDED THAT THE FILTER BE CLEANED REGULARLY (PRIOR TO EACH USE & PERIODICALLY DURING USE) SO THE FILTER CAN FUNCTION CORRECTLY. CAUTION: DO NOT USE 3 MICRON CARTRIDGE FILTER IN WET VACUUMING APPLICATIONS.