Key Features: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 removal of traditional mechanical cables in favour of electrical wires eliminates poor shifting caused by contaminates, corrosion and stretching, and also provides effortless gear shifts,Simply pressing tactile buttons allows effortless and comfortable shifting even when your hands are cold,Top bar button shift switches are used to operate the rear derailleur,Can be used in conjunction with ST-9270 drop bar STI shifters,Shift switches with 260 mm SD-300 series E-tube electrical cables fitted.