Di2 Components: Shimano Dura-Ace Di2 ST-7970 STI Lever, FD-7970 Braze-on Front Derailleur, RD-7970 Rear Derailleur. Front Derailleur Clamp Sold Separately.

Di2 Power System: 7970 Di2 Wire Kit (front and rear); 7970 Di2 Battery, charger and cable. System Programer Sold Separately.

Shimano's Dura-Ace Di2, a technologically advanced, electronic shifting option for the all new 7900 series Dura-Ace. Comprised of Dual Control type shift / brake levers, front derailleur, rear derailleur, and a battery pack, the new Dura-Ace Di2 7970 components provide precision electronic performance and integrate seamlessly with components from the 7900 series Dura-Ace group while adding only 68 grams to the entire group.
Electrically actuated shifting significantly eliminates issues associated with cable friction and contamination because the derailleurs respond to electrical impulses that are delivered in fractions of a second. The shifters are now merely switches which also allows for creative placement of optionalremote shifters while also reducing the weight and profile of the main shift units. Derailleur movement is precisely controlled through computer automated movement and servo motors creating perfectly synchronized and calibrated shifts every time.