Black Ops Carbon filters feature virgin activated Australian RC-412 granular carbon. The activated carbon absorbs and traps pollutant molecules within the carbon removing contaminants, odors and other airborne impurities. Lightweight design Precision machine packing allows for more carbon loaded within and less movement Open air mesh design maximizes airflow Powder coated aluminum tops & bases Built in flange and 2 pre-filters are included 2 year life expectancy *Life expectancy is average, could be more or less based on environment and usage.