Dura-Ace rear derailleur with lightweight carbon cage & wide link design gives quick accurate shifts, & unmatched drivetrain efficiency Full carbon fibre inner & outer pulley plates enhance rigidity & significantly reduce weight High tolerance cold forged aluminium link plates & body construction provide for extremely light weight, strength & durability High rigidity wide outer link plates the pulley body to increase pivot joint rigidity Sealed pulley bearings reduce friction & rotate silky smooth increasing efficiently Four self-lubricating micro-machined fluorine-coated link pivot bushings provide low-friction shifting Pulleys are made from tough Du Pont Zytel for longer life & less chain noise With a total capacity of 33 tooth, it is able to operate with wide gear ratios up to a 28 tooth cassette sprocket Hard wearing Dura-Ace finish & graphics for long lasting good looks 10-speed compatible Weight: 166 grams