Shimano GRX RD-RX820-GS is compatible with 10-45T and 12-speed mountain bike cassettes, providing a wide range between gears so you can maintain a comfortable cadence regardless of the terrain. The Shimano GRX 12-speed rear derailleur features an integrated chain stabilizer that ensures smooth shifts between gears and more secure chain management, even in the most uneven terrain.

Features:

• SHIMANO SHADOW RD+
• Top sprocket: Max. 10T/Min. 10T
• Low sprocket: Max. 45T/Min. 45T
• Total capacity: 35T