The Shimano EW-WU111 D-Fly wireless unit is an inline junction designed for integration with Shimano Di2 electronic shifting systems. It allows cyclists to monitor and configure drivetrain settings wirelessly using a smartphone, tablet, or compatible cycling computer. Its main function is to transmit gear position and battery life data via both Bluetooth LE and ANT+ protocols, supporting integration with the E-Tube Project app for system setup, diagnostics, and firmware updates.

This unit is compatible with a wide range of Shimano Di2 road and mountain groupsets, including Dura-Ace, Ultegra, XTR, and XT Di2 systems, and requires a compatible internal battery (such as BT-DN110). It supports only one wireless chip per system, so multiple units cannot be used together. The EW-WU111 is well suited for cyclists who want real-time access to drivetrain data—such as gear position and battery status—on their Garmin, Wahoo, or Shimano PRO computers, as well as those who prefer performing maintenance and updates with a smartphone rather than a wired connection.

Installation is straightforward for those familiar with Di2 wiring; the unit connects inline as a junction and does not require any special tools. The EW-WU111 adds a practical layer of connectivity without significantly increasing system complexity or weight.