Features1PROFESSIONAL DESIGN: 30.5mm flywheel connector adapter and 22T single speed flywheel design, suitable for a wide range of popular electric bikes. 2METAL MATERIAL: Bike freewheel adapter set is made of iron material, oil resistance, long service life, reliable and durable performance. 3FINE CRAFTSMANSHIP: With its exquisite craftsmanship, the flywheel is durable and won't be deformed over time, keeping its function and performance. 4SIMPLE INSTALLATION: The flywheel with connector is easy to install, convenient for professional bike mechanics and DIY enthusiasts. 5STABLE AND EFFICIENT: Provides stable and efficient power transmission. Fine engineered design reduces friction and maximizes energy transfer for seamless operation of your machine.SpecificationItem Type: Bike Freewheel Adapter SetMaterial: IronPackage List1 x Connecting Head1 x Flywheel