The iQ426HEPA Cyclonic Dust Extractor is equipped with a four stage filtration system, two of which being the primary cyclone followed by the six secondary cyclones. Utilizing this two stage cyclonic filtration process the cyclones pull and capture large and medium sized particles out of the airstream, keeping them from reaching the third and fourth stages (Durabond Filter and HEPA Filter). Having cyclones filtering dust and debris at the first two stages not only protects your filter from clogging up and keeps your suction strong, it also gives the iQ426HEPA the versatility to pick up different types of debris of various sizes, without you ever worrying about clogging. What makes this Vacuum Dust Collection System (VDCS) truly unique is the two stages of cyclonic filtration because this means that less than 1% of the dust ever reaches the filter. With a clean filter, vacuum suction stays strong and operating at its optimum performance level. The cyclonic filtration process and a clean filter is what gives the iQ426HEPA its powerful 190 CFM of suction power, making it the most efficient dust extractor in its class.