SRAM X3 Rear Derailleur - 789 Speed Long Cage BlackSRAM X3 Rear Derailleur 789 Speed Long Cage Black. Affordable and reliable derailleur is great for repairs and upgrades. Will work with 7 8 or 9 speed cassettes depending on the shifter used 1: 1 shifter to derailleur actuation ratio for precise light action indexing TECH SPECS Largest Cog 34 Color Black Rear Der Shifter Compatibility SRAM 1: 1 Rear Derailleur Mount Type 10x1 Standard Drivetrain Speeds 7 Drivetrain Speeds 8 Drivetrain Speeds 9 Weight