Dura ace di2 dual integrated intelligence moves to the next generation tested in competition and taken to victory by pro riders in all conditions including the 2012 tour de france team sky every part of a di2 setup hinges on the battery without power it just wont work charge up this highly efficient battery for up to 2000km of use key feature the power house of dura ace di2 is a long life 74v li ion battery that is both compact and reliable taking shifting effort away from you