High strength aluminum alloy, CNC processing, enhance the durable strength Deepen the tooth mark: can effectively reduce the situation of chain off, more clear speed change, more stable on the chain. Specification: 16T Product diameter: About 63mm/2.48in (16T) Product height: About 8mm/0.32in Net weight: About 12g (16T) Diameter of middle hole: 6mm/0.24in Inner diameter of two derailleur tube: 5mm/4mm (generally, a derailleur tube is inserted into the guide wheel by default) Application: compatible with most backdials on the market Guide wheel selection principle: 1. The same size as the original guide wheel is preferred. If there is no same size, the smaller one can be instead of the larger one 2. There is no distinction between guide wheel and tension wheel, but some original guide wheel and tension wheel are different in size, they can also be replaced with the same size, and the chain length needs to be readjusted. Colour: Multicolor Material: aluminum alloy + ceramic Package Contents: 1 x Bicycle Rear Derailleur 2 x Sleeve Tubes 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.