Shimano RD-R8150 Ultegra Di2 Rear Derailleur Outer Plate & Retaining Screw Description: The Shimano RD-R8150 Ultegra Di2 Rear Derailleur Outer Plate & Retaining Screw is a factory replacement part. If a rear derailleur cage has become damaged but the rest of the derailleur can still be used, this part will help to restore the proper shifting performance of the rear derailleur. Features: Includes the outer derailleur cage plate and the retaining screw that holds it into the main body of the rear derailleur Derailleur body, pulleys, inner cage, and other hardware sold separately See compatibility tab for full list of compatible derailleurs