Shimano GRX RX815 Di2 Rear Derailleur – 11 Speed

With an integrated chain stabilizer mechanism, the Shimano GRX derailleur provides a quieter experience and shifting security and precision on mixed terrain. For rides on smooth surfaces, the derailleur features and on/off switch for the chain tensioner. The RX815 DI2 version offers the digital precision of Shimano electronic shifting and synchronized shifting. And is compatible with road cassettes with a 34T low sprocket max.