OEM Part: FAN BLADE CW ROTATION, INNER DIAMETER: 1/2″, INNER;DIAMETER: 13MM, MATERIAL: ALUMINUM, NOTE: 4-BLADES, OUTER;DIAMETER: 18″, OUTER DIAMETER: 457MM, ROTATION: CLOCKWISE;FROM SHAFT END, WEIGHT: 1.4LB, Original Equipment Manufacturer (OEM) Part Numbers are given as a reference tool only.