Shimano Dura-Ace RD-R9150-SS Di2 Rear Derailleur - 11-Speed Short Cage Black

System supremacy
Dura-Ace: Each of the components magnifies the qualities of the others for an unparalleled level of performance. Optimizing input to maximize output. That's how it achieves supremacy.

• System engineering at its peak.
• Ergonomic shifting operation without stress
• Shimano Shadow RD low-profile design
• Shimano Synchronized Shift
• Pulley maintains consistent distance to cassette for increased shift stability
• Maintains compact and smooth appearance
• Less damage in a crash