The Shimano GRX 820 Rear Derailleur is an essential component to ensure the smoothest possible shifting on your favorite gravel bike. This derailleur manages a 12-speed system with ease, providing near-silent function and seamless gear changes. It is equipped with Shado RD+ Technology which is responsible for its silent function as well as a chain stabilizer that can be turned on and off. This reduces chain slap and chain drop and lighter and is more efficient than a roller type chain device. It can be switched off to provide a more pleasant ride on smoother surfaces. The Shimano GRX 820 Rear Derailleur is a must have for gravel riders.