The Magnum Pro line of professional carbon air filters have 50% more Australian Activated Mined Carbon than most Carbon Filters on the market. Compare this filter with other 4" Filters an you will see the difference. This Carbon Filter has a 2" Carbon thickness (Most others have a 1" or 1.5" Carbon thickness) Australian Mined Carbon is the end result of processed coal. This process treats the mined material with oxygen to open up millions of microscopic pores between the carbon atoms. The result is a uniform carbon with a surface area of up to 2,000 square meters per gram. This amazingly porous substance (which is not only lighter than plant-based carbon, but 2 to 3 times as porous), is now ready to absorb over 100% of its own weight in odor producing particles.