K&N Round Tapered Universal Air Filter 3.5in Flange ID / 5.75in Base OD / 3.75in Top OD / 6in HK&N's Universal Air Filters are designed and manufactured for a wide variety of applications including racing vehicles, radio controlled cars, generators, snowmobiles, tractors, and other applications. Regardless of the angle or offset diameter of the air intake, there is probably a K&N Universal air filter for your equipment. All filters are constructed with ultra strong molded pliable rubber flanges which absorb vibration and allow for secure