Round air filters represent traditional construction that is used in passenger cars.

During engine operation round air filters are exposed to high loadings and forces of compression as filtered air passes through them in inside direction.

Strengthening elements are applied in order to provide stability against deformation of a filtering partition surface.

More often there is applied metal grid, treated with anticorrosion covering, which raises rigidity of filtering cartridge and prevents filter from damage as a result of the pressure difference that is formed during engine operation.

The main disadvantage of round filters is big hull volume concerning to square of filtering element. Consequently filter occupies big hood space that is inadmissible for modern passenger cars considering installation of many additional systems.

Round air filters have been replaced by panel type air filters, which thanks to a design have more advantageous proportion of filtering square and casings volume.