SHIMANO Dura-Ace Di2 ST-7970 STI Shifters Dura-Ace DI2 takes Shimano shifting performance to a whole new level with SEIS (Shimano Electronic Intelligent System). In addition to uni-directional carbon fiber levers, the electronic shifters are ultra lightweight. Includes a 10-speed right shifter/brake lever and a 2-speed left shift/brake lever.