Shimano battery for Dura-Ace Di2 Di2 External Battery, battery charger, and power cable are universal between Dura-Ace 9070, 7970, Ultegra 6870, 6770 and Alfine Di2 systems Battery weighs 71g Building a complete Di2 kit? QBP's handy parts-selector will help you cover all the bases All Di2 components on the bicycle require the same firmware version. Using Di2 components with different firmware versions may cause malfunctions Use Di2 system checker to update component firmware from http://e-tubeproject.shimano.com/