Shimano sti levers ultegra di2 6870 11 speed instant accurate shifts improved ergonomics for easier access to the shift buttons from the top of the hoods 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 al