Shimano GRX RD-RX717 Di2 12-speed Wireless Rear Derailleur

Precise and clean wireless shifting with Integrated on-board removable battery (BT-DN320 sold separately)The integrated removable on-board battery is protected within the linkageCrash recovery function, absorbs impacts and returns to its original positionConnectivity BLE, ANT privateShadow ES features a super low profile skid plate design and optimized slant angle for optimal clearanceShadow ES uses a dual spring chain stabilising switch that when on will reduce chain bounce in rough terrain maintaining more stable drive and shiftingThe Shadow ES system is also zero maintenance and has no degradation of performanceUnique structure using two springs has a tighter chain wrap that improves shifting and security with increased spring force by 70%, allowing the chain to mesh firmly with the sprocketWith the tighter chain wrap skipping is prevented even as the cogs wear13T solid pulleys and decreased derailleur tension prevent high chain tension in low gearsSteel outer and inner pulley cagesCold forged wide alloy outer linkFluorine-coated link pin bushingsSpecifically designed to work with 12-speed drivetrains10-51 tooth compatible SGS cage