Description: 【High Quality Material】: The bike chain cover is made of high quality PP ABS material, durable, lightweight and long using time. 【Bike Chain Protector】: The bike chain guard is designed for protect your bike chain from dust, water, stone, etc. 【Installation Instructions】: 1. Take out the center shaft. 2. Put it into the fixed bracket 3. Reinstall the center shaft 4.Please make sure the bracket is properly installed and do not install upside down. 5. Reinstall the chainring. 6. Reinstall the chain. 7. Install the chain cover. 8. Fix the chain cover with screws. 9. Fix the tail of chain cover. (please pre place the hole.) 【Size】: The length from the bracket end to the center of the chain cover is 330-430mm/12.99inch-16.93inch, the outer diameter of the circular part is 100mm/3.94inch, the inner diameter is 65mm/2.56inch. 【Suitable For】: The bike chain guard protector is suitable for 40-44T, please confirm the size and crank set gear for sure it is suitable Note: The conjoined center shaft bike and hollow shaft bike can not be installed. Package Includes: 1 Set Bike Chain Cover Note: Please allow slightly errors due to manual measurement and different monitors.