R-series rear derailleurs are designed to work with Shimano-compatible road shifters. These R9 rear derailleurs combine compatibility, weight savings, and a robust design. - Weight-saving aluminum bracket body and outer link - Steel pulley cage for extra chain-rub durability - Compatible with Shimano 9 and 10-speed road systems - Not compatible with Shimano Tiagra 4700 road system - Short cage for double crankset 28T max cog setup - Medium cage for double crankset and 34T max cog - Long cage for triple crankset and 28T max cog