K&N Round Tapered Universal Air Filter 4in Flange ID x 5.375 Base OD x 4in Top OD x 6.5in HThe 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