Shimano Ultegra Di2 R8150 Rear Derailleur

Ultegra Shadow design with Di2 technology, shifting is easy and precise - just a light touch, as soft as a mouse click, is sufficient for the front or rear derailleur to instantaneously select the correct gear 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 Sleek appearance with Low profile Shadow design construction reduces risk of damage in a crash Programmed automatic motion at the touch of a switch makes this derailleur quick, smooth and effortless to shift The removal of traditional mechanical cables in favour of electrical wires not only eliminates poor shifting caused by contaminates, corrosion and stretching, but provides effortless gear shifts Derailleur contains a saver (fuse) function, where the inner structure is protected from strong impacts 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 12-speed E-tube Di2 compatible Wide gear ratio compatible up to 11-34T