Polished aluminum. Sprockets are flat and drilled with 3/8" holes in H-D bolt pattern. Made from 7075-T6 aluminum and for use with 530 chains. Available from stock in the Roland Sands Diesel and Performance Machines Element and Paramount / Heathen styling. Perfect to style match with RSD & PM wheels and brake rotors. Available for Big Twin / LSD (Left Side Drive) and XL / RSD (Right Side Drive) applications. Note: Inside Diameter PM sprockets: All PM sprockets are 2.500" ID. They will fit directly to PM 5.50" wide and wider wheels since on these wheels larger wheel bearings are used. If you order a PM wheel for use with a sprocket, order a pre-2000 wheel, since these come in the pre-2000 1.985" size. Then order PM sprocket spacer plate (MCS 952733) to reduce ID of sprocket from 2.500" to 1.985". For stock & PM 73-99 wheel hub: Order PM sprocket spacer plate (MCS 952733) to reduce ID of sprocket from 2.500" to required 1.985". For stock & PM 00-up wheel hub: It is not possible to install a rear wheel sprocket, since no sprocket spacer plate is available that will reduce the 2.500" ID of the sprocket to the required 2.220" ID of 00-up wheels.