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