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 gearThe removal of traditional mechanical cables in favour of electrical wires eliminates poor shifting caused by contaminates corrosion and stretching and also provides effortless gear shiftsSimply pressing tactile buttons allows effortless and comfortable shifting even when your hands are coldClimbing twin button satellite shift switch is used to operate the rear derailleur whilst your hands are on the top of the bars one button up one button downTo be plugged direct in to E-tube drop bar STI shiftersShift switch is supplied with 260.5 mm E-tube electrical cables installedWeight is 30 grams a pair