Shimano EW-RS910 Junction A for Internal Bar/Frame Mount; Its a must have for the Di2 system. It fits in the handle bar or specific placement on bike (down tube). Engineering, I wish it was more user ergonomic; the button is 'stiff', and the door opens downward to 'charge' the proprietary Di2 system battery....however, you still need this to complete the system. Allows user to plug into PC update components, and charge battery.
Get rid of the under the stem blemish from the older junction and tighten up the aesthetics !
Can modify most aluminum and carbon bars to accommodate the wiring easily .
I wanted to clean up my front end and this did the trick. It should become the standard approach - more aero for sure.
It just works. I also upgraded to bluetooth at the same time...
