The Box Three Prime 9 Rear Derailleur is a simple, but fully-featured and wallet-friendly rear derailleur. It includes a limited slip clutch, sealed bearing pulleys and a solid construction. It is compatible with 11-46 and 11-50t cassettes making it one of the most versatile derailleur offerings for Prime 9 drivetrains.

• Prime 9 technology offers the same range as a 12-speed drivetrain, with fewer gears to shift through
• The limited slip clutch engages instantly and offers constant torque for less chain slap, better chain engagement and no dropped chains
• Stamped front and rear cage
• Direct channel cable stay
• Bearing pulleys