Not only is this CNC anodizing treatment rear derailleur can be used conveniently, but also it has long lifespan and strong tough performances.This rear pulley wheel is sturdy and lightweight, and upgraded RS bearings ensure durability, and it support various speed changes to provide you with a better riding experience.Made of high quality metal material, it is durable and wear-assistant.The diameter of the product is 4.3cm, and the inner diameter is 0.51cm.It is compatible with mountain bikes, road bikes and so on.Item Name: Bearing Guide RollerMaterial: MetalFeatures: CNC Anodizing, Anti-deformation, Wear-resistantColor: Black, Blue, Purple, Red, Silver Color, Golden ColorSize Details: Diameter: 4.3cm/1.69" (Approx.)Inner Diameter: 0.51cm/0.2" (Approx.)Notes:Due to the light and screen setting difference, the item's color may be slightly different from the pictures.Please allow slight dimension difference due to different manual measurement.Package Includes:1 x Bearing Guide Roller