The Shimano GRX RD-RX400 10-speed rear derailleur keeps shifting silent and uninterrupted when riding on rough terrain. A Shadow RD+ chain stabilizer prevents chain slapping and drops The gravel-tuned clutch tension helps to provide smooth and reliable mixed surface shifting Stabilizer can be turned on/off to match terrain Compatible only with 10-speed ST-RX400, ST-4700, ST4720, ST-4725, ST-RS405 and SL-4700 shift levers Rear Derailleur Mount Type: Shimano Rear Direct Mount , 10x1 Standard Drivetrain Speeds: 10 Cage Length: Long Chain Wrap Capacity (teeth): 41 teeth Largest Cog: 36 Color: Black Weight: 303 g Rear Der/Shifter Compatibility: Shimano Road