High-Speed Compatibility Designed for 8-11 speed bicycles, this rear derailleur pulley guide wheel ensures smooth shifting at high speeds. Mechanical Derailleur System The mechanical derailleur system provides precise control and reliable performance for all your cycling needs. Lightweight Design Its lightweight design makes it easy to install and use, without adding unnecessary weight to your bike. Chemical-Free Material Made without high-concerned chemicals, this product ensures safety and environmental friendliness. Versatile Gear Range With support for 11T and 13T gears, this derailleur pulley guide wheel adapts to various cycling terrains.