Not legal for sale in California The RP-4660 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-4660 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 5 1/2 inches.