-All Di2 components on the bicycle require the same firmware version-Using Di2 components with different firmware versions may cause malfunctions-For use with Alfine Di2, Dura-Ace 9070, R9100 and Ultegra 6870/6770 equipped bicycles-SM-BCR2 Internal battery charger is specific to the SM-BTR2 and IBTDN1101 internal battery (BA9075)-Includes USB (SM-USB1) power adaptor-Plugs into SM-EW90 cockpit junction boxes or SC-S705 display unit