This Shimano Ultegra RD-R8000 pulley wheel set is designed as a direct replacement for the rear derailleur pulleys on several Shimano 11-speed drivetrains, including Ultegra RD-R8000, RD-R8050, RD-RX800, RD-RX805, and GRX RD-RX812 models. The set includes both the guide and tension pulleys, each featuring 11 teeth and sealed precision bearings that help maintain smooth shifting and reduce friction over time. Cyclists who need to restore smooth drivetrain performance after pulley wear or bearing failure will find this kit fits easily into their existing setup. It is best for road and gravel riders using compatible Shimano groupsets.