Shimano GRX RD-RX815 Rear Derailleur - 11-Speed, Long Cage, Black, With Clutch, Di2, For 1x and 2xGRX RD RX815 Di2 Rear Derailleur For 1x and 2x drivetrains Operates with Shimano Di2 for digital electronic shifting Gravel tuned clutch tension provides smooth and reliable mixed surface shifting Item Specifications Cage Length Long Chain Wrap Capacity (teeth) 38 Color Black Drivetrain Speeds 11 Largest Cog 34 Rear Der Shifter Compatibility Shimano Road Di2 Rear Derailleur Mount Type 10x1 Standard Rear Derailleur Mount Type Shimano Rear Direct Mount