The SRAM GX Eagle B2 12-Speed Rear Derailleur (Lunar) is a premium mountain bike mechanical workhorse engineered with an updated cage design to optimize modern high-range drivetrains. Identified by SRAM under model ID RD-GX-1-B2, this derailleur delivers precise, crisp shifting under intense climbing loads or aggressive trail riding.

Product Specifications & Features

• Gearing Compatibility:
  Fully compatible with wide-range 12-speed cassettes, specifically engineered to support the large 10-52T range, while remaining backward compatible with standard 10-50T cassettes.
• X-HORIZON Technology:
  Features a "straight parallelogram" design that isolates all movement to the horizontal axis. This eliminates ghost shifting and drastically decreases the force required to change gears.
• Advanced Chain Management:
  Built with an updated aluminum cage architecture for improved chain retention, larger offset upper pulleys for uniform chain gaps, and a Type 2.1 Roller Bearing Clutch to eliminate annoying derailleur bounce and chain slap.
• Lunar Aesthetic:
  Finished in the GX Eagle signature "Lunar" gray master colorway, this design allows it to blend seamlessly with any chain and cassette combo within the broader SRAM Eagle Colorsystem.
• Sturdy Construction:
  Utilizes strong steel pulley bearings and a robust aluminum cage meant to take trail impacts. However, users should clean it regularly to prevent rust build-up in wet conditions.