Shimano's Ultegra Di2 utilizes a wireless cockpit paired with a wired connection between a single, seat-tube-stored battery and the front and rear derailleurs, ensuring absolute reliability in all conditions.
Just like Dura-Ace, the Ultegra Di2 system is highly customizable using Shimano’s E-TUBE PROJECT Cyclist App on your smartphone. With the app, you can set-up your drivetrain just the way you like it, adjusting shift speed, altering the number of shifts per button actuation, and utilizing Synchronized and Semi-Synchro shifting functionality.
You can also pair the system with third party cycling computers such as Garmin and Wahoo, which allow you to monitor gear selection and battery status.