Shimano Di2 Junction BoxSM-EW90-B 5-Port Cockpit Junction Box connects up to 2 pairs of Di2 shifters to the frame junction box via 5 SD50 E-tube wiresOEM front wiring kit for Dura-Ace Di2 9070LED battery charge level indicatorRear Derailleur adjustment modeInternal Battery charging portIncludes Junction Box Band (CY9082) and Junction Box Hook (Mounting Plate CY9081)All Di2 components on the bicycle require the same firmware version. Using Di2 components with different firmware versions may cause malfunctionsUse Di2 system checker to update component firmware from http://e-tubeproject.shimano.com/