Features1Used on rear derailleur for chain transportation and speed changing. 211T suits for 8/9/10/11 speed rear derailleur. 3Inner ceramic bearing is ultralight and owns high degree of lubrication, which can ensures its smooth working. 4Aluminum alloy construction is antirust and corrosion resistance, durable for long time use. 52 replaceable 4mm and 5mm bushing is included to enrich your installation choices.SpecificationFeatures:Used on rear derailleur for chain transportation and speed changing.11T suits for 8/9/10/11 speed rear derailleur.Inner ceramic bearing is ultralight and owns high degree of lubrication, which can ensuresits smooth working.Aluminum alloy construction is anti-rust and corrosion resistance, durable for long timeuse.2 replaceable 4mm and 5mm bushing is included to enrich your installation choices.A necessary accessary for your bicycle.Specification: Condition: Material: Aluminum Alloy Teeth: 11T Hole Diameter: Approx. 6mm / 0.24in(4mm and 5mm bushings are included) Size: Approx. 4 * 0.8cm / 1.6 * 0.3in Weight: Approx. 18g Packing List: 1 x Bike Rear Derailleur Pulley 2 x Bushings(4mm and 5mm)Note:Please allow slight size inaccuracy due to manual measurement and we appreciate for your understanding.Package List