Dura ace rear derailleur with lightweight carbon cage and wide link design gives quick accurate shifts and unmatched drivetrain efficiencyfull carbon fibre inner and outer pulley plates enhance rigidity and significantly reduce weighthigh tolerance cold forged aluminium link plates and body construction provide for extremely light weight strength and durabilityhigh rigidity wide outer link plates the pulley body to increase pivot joint rigiditysealed pulley bearings reduce friction and rotate si