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Shimano BT-R1A External Di2 Battery - All Di2 components on the bicycle require the same firmware version. Using Di2 components with different firmware versions may cause malfunctions - Use Di2 system checker to update component firmware - Di2 External Battery, battery charger, and power cable are universal between Dura-Ace 9070, 7970, Ultegra 6870, 6770 and Alfine Di2 systems - Battery weight: 71 grams

This is the correct plug-and-play wire for Shimano's E-Tube Di2 electric-shifting systems. It comes in sixteen different lengths, so choose the one(s) that's right for your Di2 E-Tube wiring configuration.