• Di2 internal battery, compatible with all e-Tube Di2 groups (except R9250/R8150 series)
• Capacity: 500 mAH (± 2000km)
• Use with EW-WU101 or SC-MT800 interfaces/junction to gain BlueTooth Smart wireless connectivity for on-the-fly adjustments with smartphones and tablets
• Requires SM-BCR2 charger