The most advanced level of shifting technology: at the touch of a switch Dura-Ace Di2 is quick shifting, smooth, and effortless, making for unmatched drivetrain efficiency.Key Features:The removal of traditional mechanical cables in favour of electrical wires eliminates poor shifting caused by contaminates, corrosion and stretching, and also gives effortless gear shifts,Simply pressing tactile buttons allows effortless and comfortable shifting even when your hands are cold,Buttons are located in a near identical place to the positions you|d assume for shifting using a mechanical Shimano STI,Shifters are lightweight thanks to carbon fibre lever blades, carbon composite bracket body, and a titanium clamp band / fixing bolt,Brake lever pivot is positioned to increase power giving excellent ergonomics when riding on the hoods,Finely tuneable reach adjusters for the levers enable custom fitment for all hands,The Di2 STIs are also compatible with the FlightDeck computer (SC-7900), measuring important data such as heart rate, altitude, cadence, gear position, battery indicator, and more,Levers are supplied without electrical cables, as these need to be ordered separately to suit,Weight is 255 grams a pair.