E-Tube wires are used for Dura-Ace 9070 11-speed, Ultegra 6870 11-speed and Ultegra 6770 10-speed. A Di2 system typically requires six connecting wires. A typical newer Di2 internal install on a 56cm frame with an internal battery will use a 950mm-1000mm for the cockpit junction to the lower junction. A 750mm is used from the seat post battery to lower junction and a 600mm is a safe bet for the rear derailleur to lower junction. A 300mm is generally the choice for the lower junction to the front derailleur. Two 350mm wires are needed from the levers to the cockpit junction with 400mm being the choice on the widest handlebars. Inserting a D-Fly EWW01 will take a 250mm or 150mm available soon. We suggest measuring for the exact lengths when possible and it's better to get the wires slightly long when in doubt.
E-Tube Di2 wire represent an improvement over first generation Dura-Ace Di2 wires because E-Tube use smaller 2 core wires instead of the 4 core used on first generation Dura-Ace. E-Tube wires are compatible for both internal and external routing so there is no need to buy separate internal or external wires. The E-Tube Di2 wires are lighter with smaller connections so there are smaller holes required in the frame for internal routing. Connections on the E-Tube system are water tight without the requirement to install a shrink wrap seal like on 10-speed 7970 Dura-Ace Di2.
E-Tube wires are not compatible with 10-speed 7970 Dura-Ace Di2 components