Your cabin microfilter filter removes contaminants in the air before they enter the heating and air conditioning vents, but over time it will become full of dirt, dust, and pollen. An old and dirty cabin filter can impact your health and increase allergy symptoms. Replacing the cabin filter is part of the maintenance schedule, but is too often overlooked. Manufactured by Volkswagen-Audi Group filtration supplier, this MANN filter is infused with charcoal for greater effectiveness.