Shimano Ultegra Di2 R8150 2x12S Derailleur

The Di2 front derailleur's operation is pioneering, smooth shifting is guaranteed thanks to wireless communication with the gear levers. What's more, shifting the rear derailleur automatically trims the front derailleur Full and semi synchronized shifting programable, Synchro shift compatible meaning a single shifter can control both front and rear shifting which can be fully custom tuned to your riding preferences. Semi synchronized shifting means when a front shift is made the rear mech will automatically correct to the appropriate ratio 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 The front derailleur also trims automatically; the cage moves in response to the position of the rear derailleur on the cassette to ensure no chain rub and a quiet unobtrusive ride, enabling you to concentrate on the road ahead Designed to work with the wider