The Ultegra Di2 SM-EW67 Front Wire/Junction connects the electronic shifter controls to the rest of the Di2 components. It also contains the battery indicator unit which can be engaged by the pads on shift controls.
An LED indicator at the junction will display green if the battery is over 50% charged, red if under 50% charged, and flashing red if the battery is almost drained. The indicator mounts to the brake cable housing just below the stem and handlebar junction via included zip ties.
The SM-EW67 Front Wire/Junction features two built-in cables which attach to the left and right Ultegra Di2 ST-6770 Shift levers. The EW-SD50 (sold separately) rear wire is required to connect SM-EW67 Front Wire/Junction (Junction A) to the Rear Junction Box (Junction B; sold separately).
Note: This product is also compatible with Dura-Ace 9070 and Ultegra 6870 Di2 but requires a firmware update. You will need the SM-PCE1 PC Tool to install this update, which can be downloaded at http://e-tubeproject.shimano.com. Alternatively, the most recent firmware can be installed at your local Shimano Service Center.