Shimano BT-DN300 Built-In DI2 Battery

Shimano BT-DN300 Built-In DI2 Battery - For Dura-Ace 9250 and Ultegra R8150 Systems

The Shimano BT-DN300 Built-In DI2 Battery is a must purchase battery to go along with the charger and power cable to complete the your Di2 system. All Di2 components on the bicycle require the same firmware version. Using Di2 components with different firmware versions may cause malfunctions. It is compatible with thinner, next generation electric SD300 wires and R9250 and R8150 series systems, and features three SD300 wire ports.