1.Anodised CNC machined bicycle jockey wheel with fully sealed bearing for center bolt derailleurs. 2.Made a big difference to shifting, went from crunching to super smooth changes they almost step between gears now. 3.High quality precision CNC job with anodizing , lightweight and durable. 4.Excellent jockey wheel pulley. Smooth bearings. 5.Fits for almost all mountain bike of 11T. Product Description Color: Blue / Red / Yellow Material: Aluminum Alloy Size: Diameter 8.8MM Diameter 43.4MM Thickness 0.6CM; Cap hole size 0.5CM Rear screw gear hole 8.9MM<br><br>Package Contents: 1Set x Bicycle Guide Wheel<br><br>Only 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.