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

• 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/
• Compatible with thinner, next generation electric SD300 wires and R9250 and R8150 series systems
• Features three SD300 wire ports
• Shared fixing method with BT-DN110
• Built-in type
• U.S. spec