K&N Air Filter for Ducati Hypermotard 939K&N Air Filter for Ducati Hypermotard 939 K&N Race Air Filters are designed to achieve a virtually unrestricted air flow while maintaining filtration levels critical to engine life and performance. The secret to their success lies in the unique characteristics of the filter medium which was originally developed by K&N all those years ago in the dust, sweat and tears of desert motocross racing. The racing air filters has two layers of special pleat