In traditional air filters for trucks and heavy duty machines the rigidity and resistance to mechanical damage was important. This is the reason of the massiveness of these filters. Filters have solid metal bottoms, enforcing cores and outer casings made of net or perforated metal sheet. Rubber washers glued to the bottom provide cartridge sealing. The filter medium placed inside such a solid construction is perfectly protected from deformation and mechanical damage which assures failure free exploitation. Nevertheless in the times of natural environment protection awareness, new cars are rarely equipped with these filters since their disposal is troublesome.