Wiki Bicycle » Shimano » Shimano Road » Dura-Ace Di2 Road
Information from: www.shimano.com.
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.