Features: Elevates your cycling performances with our rear derailleur pulley set, craft from high grade aluminum alloy for maximumly power reduced chain frictions. Feature a defaults 16t guide wheel, upgradable to 18t, our pulley set is engineered with ceramic bearing to minimizely frictions and make climbing hill effortlessly while ensuring a snugs fit with the chain for swifts shifting. Whether you're gearing up for a high stake race or simply enjoy a leisurelys ride, our derailleur pulley set promise a smooth, stable, and efficient gear transitioning in any cycling scenario. Upgrades your bike with our fashion derailleur pulleys to experience a noticeable difference in speed and performances, making every ride smooth and more enjoyabled. Effectively increase the chain power inertias. Reduce chain frictions and increase stability. Specifications: Component:Aluminium Alloy Size: As Picture Shown For R8800 (6870/6770/ 9070/Ultefra/DURAACE) R8700 For 5800/5700/105/6600/Tiagta For R8000 Package Includes: 1pcs Rear Derailleur Pulley Wheel note: 1.Please allow 1-2cm errors due to manual measurement, making sure that you donot mind befores you order. 2.Due to the differences between different monitors, the picture may not reflect the actual coloring of the item. Thanks for your understandings.