Description: Application: Suitable for mountain bikes, road bikes, folding bicycles, city bikes, etc. It is a great accessory for your bicycle.Metal Structure: The bike freewheel is made of aluminum alloy and steel materials, high strength, sturdy and long service life.Practical Tool: The freewheel features hollowed design to reduce weight, enhancing your cycling experience by making it smoother and more efficient.Easy to Install: The bicycle flywheel sprocket is easy to install and use, which can provide you with a good experience.Replacement Accessories: Bike freewheel can replace the old or damaged accessories well and upgrade the overall performance. Specification: Material: Aluminum Alloy, Steel7 Speed: Gear Ratio: 11-13-15-17-19-21-28T Size Chart: 114.5mmx114.5mmx28mm/4.51inchx4.51inchx1.10inch Package Includes: 1 Bike Freewheel Note: Please allow slightly error due to manual measurement.