1、Rotate Flexibly: The ceramic bearing rear dial guide wheel can rotate flexibly, making the speed change smoother. The deep tooth guide wheel can effectively reduce the chain drop, the speed change is clearer, and the winding is more stable 2、High Strength Aluminum Alloy: Made of CNC machining of 7075 high strength aluminum alloy, finished with diamond knives, anodized, and lightweight hollow design, both product appearance and wear resistance index are excellent 3、Good Lubrication Performance: The use of ceramic bearing has good lubrication performance, smoother, greatly reduced friction, bring higher strength, and improved riding experience 4、Strong Compatibility: New design of circlip have no jamming when riding, suitable for 8, 9, 10, 11 speed rear derailleur, outer diameter of the installation shaft is compatible with 4, 5, 6MM, the original bore diameter is 6MM, 2 reducing casing is provided, install reducing casing can be converted to 4MM or 5MM 5、For Chain Guide And Tension Wheel: Suitable for chain guide wheels and tension wheels. Some guide wheels can only be used as tension wheels and cannot be used for chain guide wheels. This guide wheel adopts a circlip fixed structure and is compatible with guide chain wheels and tension wheels Item Type: Ceramic Bearing Jockey Wheel Material: Aluminum alloy + ceramic bearing Product Size: Diameter: Approx. 41mm / 1.6in Applicable Transmission System: Approx. 4mm / 0.16in, 5mm / 0.2in, 6mm / 0.24in screw hole diameter; 8/9/10/11 speed transmission system 1 x Ceramic Bearing Jockey Wheel 2 x Reducer Socket