Shimano Di2 Batteries. Must purchase battery, charger, and power cable to complete the system.

FEATURES:

• 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 from http://e-tubeproject.shimano.com/
• The Shimano Di2 Internal Battery is designed to fit with internal mounts, offering a hidden solution for Shimano Di2 drivetrains
• Li-Ion battery power
• Shifter/Derailleur Compatibility: E-Tube , Shimano Ultegra Di2 , Dura-Ace 7970 Di2 , Dura-Ace 9070 Di2