GRX RD-RX815 Di2 Rear Derailleur FEATURES: Operates with Shimano Di2 for digital electronic shifting Gravel-tuned clutch tension provides smooth and reliable mixed surface shifting For 1x and 2x drivetrains SPECS: Color: Black Largest Cog: 34 Rear Derailleur Mount Type: Shimano Rear Direct Mount , 10x1 Standard Chain Wrap Capacity (teeth): 38 Cage Length: Long Rear Der/Shifter Compatibility: Shimano Road Di2 Drivetrain Speeds: 11 Weight: 287