With the release of Shimano's updated Dura-Ace and Ultegra 12-speed Di2 drivetrains comes a new e-tube wire that's based on technology developed for Shimano's industry-leading e-bike systems. The SD300 wire is more compact and lightweight than previous e-tube wires, and it comes in a wide variety of lengths so you can connect your derailleurs to the Di2 battery regardless of frame size or shape.