The Shimano BT-DN110 internal mounted battery for Di2 electronic gear systems. The BT-DN110 is 7.4 volt Li-Ion battery that has been proven to be reliable through rain, mud, cobble stones and extreme temperatures. The battery uses a hard wired system that only weighs 50 grams compared to a current wireless system that require individual batteries. TH BT-DN110 Battery can last between 1000 – 2000 km depending on the conditions. The battery can be recharged 500 before being replaced and can be charged via the cable junction or handle bar mounted display. The battery also has an internal Bluetooth chip to enabling connectivity with other Bluetooth components.