Shimano, RD-RX812, GRX 1x11s Derailleur.

SHIMANO GRX - Rear Derailleur - SHIMANO SHADOW RD+ - 42T max low sprocket - 11-speed

With an integrated chain stabilizer mechanism, the SHIMANO GRX derailleur provides a quieter experience and shifting security and precision on mixed terrain. For rides on smooth surfaces, the derailleur features and ON/OFF switch for the chain tensioner. The RD-RX812 rear derailleur is compatible with MTB cassettes with a 42T low sprocket max.

• Adjustable chain stabilizer prevents chain slapping and drops
• Switch stabilizer ON/OFF to match the terrain
• Gravel-tuned clutch tension

• Silent and uninterrupted rear shifting on rough terrain
  
• Smooth and reliable mixed surface shifting
  
• Compatible with current road DUAL CONTROL LEVER
  
• Top sprocket: Max. 11T/Min. 11T
  
• Low sprocket: Max. 42T/Min. 40T
  
• Total capacity: 31T