Package content: you will receive 4 pieces 11T Aluminum sealed bearing wheel in 2 colors, red and yellow, enough quantities and different colors to meet your different needsProduct details: anodized CNC machined bike wheel with fully sealed bearings for center derailleur, and the bearings are bearingsReliable material: this rear derailleur pulley is made of quality aluminum alloy, which is sturdy, durable and makes the derailleur pulley anti-rust, and corrosion resistant, so it can be applied for a long timeUniversal size: the size of this bike wheel pulley will be suitable for most bikes of 11T, and can their normal workingA nice accessory for bikes: the rear derailleur pulleys are good necessary tools for bikes, the pulleys spin very freely and have low frictionsize:Rear screw hole diameter about: 5mmMaterial:Aluminum alloycolour:Yellow + RedPackage Contents:4 x Bicycle rear derailleur guide wheel8 x rear screwsOnly 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.