Shimano Dura-Ace Di2 ST-7970 STI Shifter LeversShimano Dura-Ace Di2 ST-7970 STI Shifter Levers. The revolutionary Dura-Ace Di2 electronic shifting option with SEIS (Shimano Electronic Intelligent System) takes the already superior Shimano shifting performance to a whole new level never seen before. The increased accuracy, smoothness and reliability of electronic shifting makes gear changes faster and virtually eliminates missed shifts. In addition to uni-directional carbon fiber levers, the electronic shifters are ultra lightweight & Flight Deck compatible with a wireless speed sensor that allows for intuitive operation without changing hand position.689228278677