Every sprocket tooth has been designed to achieve the maximum synchronization, shifting speed, and silent operation. The six larger sprockets have a double frame system for extreme torsional stiffness so that operating precision is maintained even during shifting under stress. The surface treatment of the 11 steel sprockets assures longer component life, maintaining the maximum long term performance.SteelNickel-chromed finishLight alloy supports for the final two triplets11x timing11x tooth machining11x light alloy lockringThread 27 x 1Weight 230gOptions:11-2311-2512-2512-2712-29