Cabin Filters prevent harmful spores and pollen from entering the vehicle interior and keep passengers and heater and ac components protected. A cabin filter works much like the filter used with your furnace in your home. Replace your cabin filter with a Bosch Premium Cabin Filter and trap close to 100% of airborne contaminants before they enter the interior of your vehicle through the heating and air conditioning system. Bosch Premium Cabin Filters absorb up to 100% of all pollen, dust particles and harmful substances. This results in a noticeable improvement in the air inside the vehicle. The Bosch Activated Charcoal Filters go one step better. They have an additional carbon layer that absorbs toxic and foul-smelling gases such as ozone, nitrogen oxide, sulfur dioxide and hydrocarbons, plus an additional cover layer for extra protection. You should decide which cabin filer is best for you, so choose either an Activated Charcoal Filter or an absorbent three-layer Particulate Filter.