Shimano E-Tube Di2 Junction-B BoxItem #: SHM12064 Usually ships the next business day
This Shimano Di2 junction box is needed for all parts of the Di2 system to communicate with each other.
Frame Junction Box connects via SD50 E-tube wires to four different points: front derailleur, rear deailleur, cockpit junction box and battery mount. How to measure a frame for SD50 wires All Di2 components on the bicycle require the same firmware version. Using Di2 components with different firmware versions may cause malfunctions
Internal junction box is meant to be hidden inside the frame
External junction box is meant to be attached to the ouside of the bottom bracket shell