This Shimano Ultegra RD-6800/6870 Pulley Wheel Set includes two genuine replacement derailleur pulley wheels designed specifically for Shimano Ultegra mechanical RD-6800 and electronic Di2 RD-6870 rear derailleurs. Each pulley wheel has 11 teeth and features sealed cartridge bearings to reduce friction and prolong bearing life. Made from durable composite plastic, these pulleys help reduce chain wear and maintain smooth, quiet shifting performance. They are directional and compatible with both short (SS) and medium (GS) cage lengths of the RD-6800 and RD-6870 models, optimized for 11-speed drivetrains. The fixed guide pulley design eliminates float, enhancing shifting precision by accommodating the tighter tolerances of Shimano’s 11-speed system. Installation requires a 3mm hex key. This pulley set is ideal for riders maintaining or repairing Shimano Ultegra 11-speed drivetrains who want direct OEM compatibility and durability without aftermarket modifications.