Shimano E-Tube Di2 Junction-B Box

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 Features: 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 Discounted at ONLY: US$ 23.99