The CPS CAT 5 Propane Dust Extractor with a primary filter with non-stick coatings help to prevent filter blinding and motor overheating. It also has a unique backwash system where 100% of backwash goes directly to the bag. The OSHA compliant HEPA filter has three times more usable surface area than standard industry dust extractors. It also utilizes Longopac continuous bagging system for zero airborne dust change changing bags.