Whenever there is no particulate filter or if it has been removed, a special filter made of micro-perforated steel can be installed. This special BRAIN product can reduce dusts by 60% and eliminate CO, HC, and bad smells generated by combustion fumes. Compared to other ceramic filters of silicon carbide or cordierite, this filter does not have to be sealed, or to self-regenerate. This avoids the inconveniences related to filter blockage. Particulate filtering is possible thanks to micro-perforated crossed channels. Regeneration will be activated spontaneously whenever necessary.