Shimano 105 Compatible: R7150/R7170 Shimano Ultegra Compatible: R8150/R8170 Shimano Dura-Ace Compatible: R9150/R9170 Reduced Size: Lighter Electric Components Potential Future Expansion: DI2 System Capabilities Internal Routing Application This Shimano EW-SD300 Di2 12 Speed eTube Wire is compatible with Shimano's 12-speed Di2 systems, including 105 R7150/R7170, Ultegra R8150/R8170, and Dura-Ace R9150/R9170. Its more compact design reduces the size and weight of new electric components, potentially enhancing the future capabilities of Di2 systems, and it's ideal for internal routing use.