The RP-4980 Universal Air Filter is constructed from an oiled cotton filter media. It comes with a K&N embossed carbon fiber top for strength and durability. The carbon fiber element adds to the light-weight design and gives this filter a smooth glass like finish. The RP-4980 is a clamp-on filter that has an inside flange diameter of 4 inches and a flange length of 5/8 inches. The base is 5 3/8 inches and the filter height is 6 1/2 inches. K&N Composite Top Universal Air Filters - With advanced composite technology, carbon fiber provides the ultimate in strength with minimal weight. Carbon fiber provides 1/3 less weight than a conventional filter top.