High-end smooth ceramic bearing guide wheel, selected high-quality white pottery, tight-fitting structure to ensure silky smooth rotation.The rear dial of the derailleur is made of high-quality aluminum alloy material, which is durable and high in strength.Ceramic material can reduce drag and improve riding efficiency, which is very useful when riding.Quiet effect: positive and negative gear guide wheels, no abnormal noise, you can get faster speed.Good performance: more compatible with flexible rotation, suitable for most rear derailleurs on the market, suitable for 8/9/10/7-speed rear derailleur guide wheels. Suitable for use with 4/5/6mm idler screw boreProduct: Bicycle Rear Derailleur PulleySize: 11TStructure: BearingDiameter: 45mmSet 4/5/6mm Spindle RollerSuitable for most rear derailleurs on the market, supports 7/8/9/10 gearsBicycle Gearbox, Ultra Durable Ceramic BearingsMaterial:Aluminum alloy 7075+Ceramiccolour:GoldPackage Contents:1 x bicycle derailleur2 x AccessoriesOnly the above package content, other products are not included.Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.