Our felted polyester filter bags are as effective as a good respirator at removing the finest (and most harmful) dust particles from the air passing through them. These bags are "toasted" on the inside, forming a singed surface that keeps dust particles from clogging the felt, and releases dust easily when shaken clean. The material filters out particles as small as 3 microns when new, or as fine as .1 microns when a moderate cake coats the felt. Available in 14", 18" & 20" diameters to fit popular Taiwanese 1HP or 2HP & 3HP dust collectors. Mounting clamp sold separately.