The RF-1038 Universal Air Filter is constructed from an oiled cotton filter media. It comes with a K&N embossed carbon fiber top and base 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-1038 is a clamp-on filter that has an inside flange diameter of 3-1/2 inches and a flange length of 15/16 inches. The base is 12 inches long by 6 inches wide and the filter height is 6 inches.