The Shimano Ultegra R8000 11-Speed Rear Derailleur GS Cage  with wide link design gives quick accurate shifts and excellent drivetrain efficiency. Shimano Ultegra R8000 11-Speed Rear Derailleur Features Ultegra Shadow design rear derailleur  Sleek appearance with Low profile Shadow design construction reduces risk of damage in a crash Wide outer link plates increase pivot joint rigidity to reduce shifting deflection Lightweight aluminium pulley cage helps reduce weight without sacrificing shifting performance Wide gear ratio compatible with 11-25 up to 11-30t