Round air filters, with cylindrically or ring shaped filter medium are a traditional construction used in cars with sufficient amount of place in the bonnet, to fit a large volume casing. Modern cars have limited space for air inlet system due to the installation of additional systems such as air condition and therefore, the round filter systems are exceedingly rare. They have been ousted by panel-type air filters, which due to its specific design have better proportion between the filtration surface and the casing volume. Considering the exploitation, the round filters are as good as the panel- type ones, because the filter quality is determined by its usability qualities such as filtering efficiency, flow resistance and contaminants absorptivity, and these properties of round filters are optimally selected for adequate engine requirements.