The shimano dura ace rd 7900 10 speed rear derailleur a dura ace rear derailleur with lightweight carbon cage and wide link design gives quick accurate shifts and unmatched drivetrain efficiency with full carbon fibre inner and outer pulley plates enhance rigidity and significantly reduce weight shimano dura ace rd 7900 10 speed rear derailleur features high tolerance cold forged aluminium link plates and body construction provide for extremely light weight strength and durability hi