Feature:1. Good Compatibility: This bike rear derailleur wheel is suitable for 4, 5, 6mm size screws, and rear derailleur 8, 9, 10, 11 speed, which is suitable for almost all mountain road bikes.2. Excellent Aluminum Alloy: This bike rear derailleur wheel is made of excellent aluminum alloy, which is durable and erosion resistant, so it can be used for a long time.3. Oil Slick Color Pattern: This bike rear derailleur wheel surface is oil slick color pattern, which is very fashionable and good looking.4. Easy To Carry: This bike rear derailleur bearing guide wheel is small in size and light in weight, and it is very convenient to carry as a spare part when it rides.5. Easy To Install: This bike rear derailleur wheel is very easy to install, you just need to align the holes and fix it with screws.Specification:Item Type: Pulley Jockey WheelMaterials: Aluminum Alloy.Package List:2 x Wheel8 x Accessories