●[Steel Material]: This bicycle 9-speed flywheel is made of qualified steel material, which has higher strength and hardness, and has good rust resistance, will not be easily deformed, wear-resistant and durable, and has a longer service life. ●[Specially Designed]: The 9-speed flywheel of this bicycle is mainly designed for 9-speed bicycles, and is suitable for chain links between 11-28T, so please check the model before buying. ●[Hollow-carved Design]: The 9-speed flywheel of this bicycle uses a hollow design, which can help reduce weight, reduce the burden when riding, and provide a better experience. ●[Features and Installation]: This bicycle 9-speed flywheel is very easy to install and use, without complicated steps or procedures, and can make the chain rotate smoothly. ●[Service Guarantee]: If you are not satisfied with the 9-speed flywheel you received from us, you can apply for an unconditional return and refund within 180 days, and we will reply in time.