R-series rear derailleurs are designed to work with 7, 8 ,9, and 10-speed Shimano-compatible road shifters. These R9 rear derailleurs combine the benefits of R10 and R8 rear derailleurs: compatibility friendly, weight saving, and robust.
Weight saving aluminum bracket body and outer link
Steel pulley cage for extra chain-rub durability
Compatible with Shimano 7, 8, 9, and 10-speed road systems
Not compatible with Shimano Tiagra 4700 road system