Shimano's Acera rear derailleur makes use of advanced designs that make it shift better and last longer. HyperGlide technology results in faster shifting, and Double Servo technology utilizes a double servo-panta mechanism that enables the rear derailleur to track perfectly to each shift and maintain an optimum distance from each sprocket.

• Maximum cog size: 34t
  
• Total capacity: 45t
  
• Pulleys: 11t
  
• Chain compatibility: HG 9-speed