Features1INCREASED SPEED AND POWER: By using the enlarged flywheel adapter instead of the pinion, it realizes the speed boosting effect and provides higher speed and more powerful power. 2PROFESSIONAL TRANSFORMATION ACCESSORIES: Bike flywheel adapters are carefully designed as an accessory for bike and tricycle modifications. 3DURABLE AND RELIABLE: Made of durable iron material, it has a long service life and stability. It can provide reliable performance in both daily riding and long distance traveling. 4EASY INSTALLATION: Compatible with existing bicycles and tricycles, it is easy and quick to install. You can easily install it on your vehicle without complicated modification process. 5SMOOTH RIDING EXPERIENCE: The enlarged design of the flywheel adapter provides higher rotation speed and smoother riding feeling.SpecificationItem Type: Bike Flywheel AdapterMaterial: IronWeight: Approx. 120g / 4.2ozDiameter: 34mm / 1.3inHeight: 20mm / 0.8inHole Diameter: 11mm / 0.4inPackage List1 xBikeFlywheelAdapter