K&N Universal Clamp Air Filters K&N universal air filters are designed and manufactured for a wide variety of applications. Regardless of the angle, the outside diameter of the air inlet, there is a K&N universal air filter for your equipment. All filters are constructed with ultra-strong molded flexible rubber flanges that absorb vibration and allow a secure fit and can also be stretched up to 1/16 (1.5mm) to fit in intermediate sizes. K&N universal air filters are available in round, conical (cone style), and oval designs for almost any specialty application. Select a universal filter type at the bottom to see available sizes.