Campagnolo Chorus 11 Speed Cassette Features 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 eleven steel sprockets assures longer component life, maintaining the maximum performance through time. The Athena groupset uses the Chorus sprockets. Sizes: 12-25,12-27,12-29,11-23,11-25,11-27,11-29