1.Anodised CNC machined bicycle wheel with fully sealed bearing for center bolt derailleurs. 2.Made a to shifting, went from crunching to super smooth changes they almost step between gears now. 3.High quality precision CNC job with , and durable. 4.Excellent wheel pulley. Smooth bearings. 5.Fits for almost all mountain bike of 11T. Color: Red Material: Aluminum Alloy Size: Diameter 8.8MM Diameter 43.4MM Thickness 0.6CM; Cap hole size 0.5CM Rear screw gear hole 8.9MM Package Contents: 1Set x Bicycle Guide Wheel Only the above package content, other products are not included. Note: Light 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.