Mountain air filters are the gold standard of carbon filters and have been so for 14 years. Designed to give maximum quality, performance and longevity. No other filter has been able to last more than 3 years of constant use. They offer superior airflow compared to other filters, due to the very low density but high mechanical strength of activated carbon used. Mountain air filters remove 99% of everything under 20 microns from the air in one pass, Including dust, lint, mold spores and organic odours.