The ever dependable Dura-Ace Di2 external battery allows you to ride miles on end without ever having to worry about running out of juice. Tried and tested over the years by both consumers and professionals alike, the Shimano Dura-Ace Di2 external battery delivers on all fronts.
Li-Ion 7.4V technology
1000 miles/1600 km average
Fits any road bike and has quick release for easy charging.