The Shimano GRX 11-speed rear derailleur provides silent and uninterrupted rear shifting on rough terrain. An adjustable Shimano Shadow RD clutch prevents chain slapping and drops.-Compatible with Shimano road Dual Control Levers-Gravel-tuned clutch tension provides smooth and reliable mixed surface shifting-Toggle clutch on/off to match the terrain-For 1x and 2x drivetrains