The Shimano GRX 11-speed rear derailleur features an integrated chain stabilizer for quiet and secure shifting on mixed terrain. It has an ON/OFF switch for the chain tensioner on smooth surfaces and a gravel-tuned clutch tension for reliable shifting. Compatible with 1x drivetrains, it has a 42t low sprocket max and is compatible with Shimano road Dual Control Levers and LinkGlide and HG 11-speed chains.