K&N Air Filter Oil K&N Air Filter Oil is engineered to provide exceptional filtration and performance when paired with K&N oiled cotton air filters. It is designed for thorough penetration of filter pleats, with the oil remaining suspended within the cotton fabric to efficiently trap contaminants. This 1-gallon refill offers extended use, ensuring your engine operates with clean, unrestricted air. For optimal results, it is recommended to use in conjunction with the K&N Air Filter Cleaner. Features K&N air filter oil is the only oil specially formulated to work in combination with the cotton fabric in K&N oiled cotton air filter elements providing outstanding air filtration When used as directed, it quickly penetrates the filter pleats, where it remains suspended in the cotton fabric until the element is cleaned with K&N air filter cleaner 1 gallon refill bottle