Harness the power.
This E-Tube Di2 Front Wire Harness kit is for Ultegra 6770 and Dura-Ace 9070 Di2 components. It features thinner, more discreet cables and a smaller junction than what you'll find on previous-generation Dura-Ace 7970 Di2 parts.
To outfit your Ultegra or Dura-Ace 9070 Di2 bike, you'll need five distinct wire sections -- front wire harness, downtube, front derailleur, rear derailleur, and battery. Unlike the other cables, this Front Wire Harness only comes in one length. It's the portion that connects the two shift levers to the A junction, which is included with this wire kit. And whether or not you run your other wires inside or outside the frame tubes, this is the part that is always nicely hidden underneath the handlebar tape.