Shimano Rear Derailleur GRX RX815 Di2

With its integrated chain stabiliser, the SHIMANO GRX derailleur provides a quieter cycling experience and more reliable and accurate shifting on varied terrain. For rides on flat roads, the derailleur has a chain tensioner on/off switch. The RD-RX815 DI2 rear derailleur is suitable for MTB cassettes with a maximum largest cog of 34T.