The shimano st 6871 features di2 technology so 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 key features di2 technology so shifting is easy and precise just a light touch as so