Shimano BT-DN110 Di2 Internal Mount BatteryShimano BT DN110 Di2 Internal Mount Battery The power house of Shimano Di2 is a long life 7. 4V Li Ion battery that is both compact and reliable, taking shifting effort away from you Excellent sealing and reliability have been proven through repeated field tests in various riding conditions, including extreme temperatures, rain, mud, and cobble stone roads Using a hard wired battery system which is both light weight and accurate compared to current