As long as your Shimano 9-10 speed rear derailleurs keep working, improve their performance with pulleys that reduce friction and increase longevity. Ours are designed to work with less resistance, adding power transmitted to the rear wheel. We have two options for Shimano 9-10 speed derailleurs. The first are machined aluminum pulleys that start with our hardened steel races and are finished with our CeramicSpeed Balls—our Standard Bearings. These outperform the competition in testing. The second option are machined titanium pulleys with our Standard Bearings. The third are machined titanium pulleys with our standard ceramic balls installed in our coated hardened steel races. Compatible with all Shimano 9-10 speed derailleurs. In the package: 2 pulley wheels with 11 teeth 4 spacers UFO TECH BEARING OIL Pulley Wheel, 15ml dropper bottle Sticker