The RF-1047 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-1047 is a clamp-on filter that has an inside flange diameter of 3 inches and a flange length of 1-3/4 inches. The base diameter and filter length are 6 inches.