Rear Kinetix Pro American Classic 8/9 Speed Cassette Hub Q-Release 16H 130mm dropout. Superlight hub as used on Mu SL Magnesium Colour Includes Q-release Scewer. American Classic makes some of the most exquisitely light and well engineered hubs available. American Classic hubs are lighter than Dura- Ace, Record, or XTR and are used by many top racers and pro teams around the world. On its rear hubs, American Classic uses a patented six-pawl cassette mechanism that makes it stronger than traditional cassettes. Rear Hub only supplied in Magnesium Colour (Not Black).