The superlight rear derailleur with 3k carbon body,CNC cage and pulleys for faster shifting. The seal bearing inside the CNC pulleys brings less friction, better drag rolling and smooth shifting. 29 teeth total capacity and Max/Min rear cassette 27T-11T (10 speed). High rigidity links increase durability and reduce need for servicing. Weight 200g compared to Dura Ace at 180g and Ultegra SL at 200g.