- Tired of the hassle and mess of air filter grease? PC Racing's Pro-Seal is the answer for a perfect filter to air box seal without the use of messy grease. This neoprene gasket adheres to the rim** inside the motorcycle's air box. The neoprene material creates a larger sealing surface and has memory for a perfect seal time after time. Due to the adhesives that are not affected by gas and oils, the Pro-Seal will not separate from the air box once installed. The Pro-Seal is available for most offroad motorcycles.