Shimano Dura-ace Di2 12 Speed Rear Derailleur

Digital Integrated Intelligence or Di2: with programmed automatic motion at the touch of a switch the Dura-Ace Di2 rear derailleur is quick smooth and effortless making for unmatched drivetrain efficiency The rear derailleur is now the brains of the system with wireless connectivity to the shifters. It acts as the point the system is charged provides ANT+ connection to 3rd party devises and replaces the handlebar junction Button on the derailleur for Di2 operations and LED light denotes synchronized shift mode setting mode and charge requirements Programmed automatic motion at the touch of a switch makes this derailleur quick smooth and effortless to shift Synchronized Shift designed developed to choose the next biggest or lowest gear ratio irrespective of whether a gear change needs to be made by the front or rear derailleur The removal of traditional mechanical cables in favour of electrical wires not only eliminates poor shifting caused by contaminates corrosion and stretching Low profile Shadow derailleur design Derailleur contains a saver (fuse) function where the inner structure is protected from strong impacts 11-34T wide gear ratio capacity will cater for compact setups as well as the traditional road double Full carbon fibre inner and outer pulley plates enhance rigidity and reduce weight Titanium B axle bolt for further weight savings High tolerance cold forged aluminium link plates and body construction is extremely light and durable Four self-lubricating micro-machined fluorine-coated link pivot bushings provide low-friction shifting Pulleys are made of tough DuPont Zytel for longer life and less chain noise 12-speed E-tube Di2 compatible