The Genuine Shimano Ultegra RD-R8000/R8050 11-Speed Rear Derailleur Pulley Set is a high-quality replacement part designed specifically for Shimano rear derailleur models. Made by the manufacturer Shimano, this pulley set includes the necessary components to ensure smooth and efficient gear shifting on your bicycle. The part number Y3E998010 helps you easily identify the correct set for your specific rear derailleur model, making it easy to maintain and upgrade your cycling components.