Shimano Ultegra RD-6800-SS 11-Speed Rear Derailleur

Shimano's Ultegra Rear Derailleur delivers category-defining 11-speed shifting. At the heart of the derailleur is a light, tough, cold-forged-aluminum body with a wide, rigid pivot design that maximizes shifting speed and equalizes shift effort across the cassette. Smooth-spinning pulleys use sealed bearing to keep out the dirt and ensure quiet running in the miles to come. SS (short cage) derailleur is compatible with a 28T max cassette size.