1. and long-lasting: Made of high-quality aluminum alloy, it ensures that the flywheel is sturdy and can withstand long-term use. 2. Versatile and compatible; designed to work with the same model single-speed bicycles and street bikes, this reverse flywheel and locking ring can enhance your experience by providing a compatible upgrade for your bicycle. 3. With threads, the locking ring specification is 1.29x24, ensuring a with most bicycle . 4. Smooth and reliable performance: Install the flywheel clockwise on the right side and the locking ring on the right side counterclockwise. This ingenious design minimizes friction and maximizes efficiency. 5. design: The flywheel weighs about 13 grams and the locking ring weighs about 11 grams, which can reduce the overall weight of the bicycle, thereby improving maneuverability and control. Weight:Flywheel: about 13g, Locking ring: about 11g. Colour:Black & Red Material:7075 Aluminum Alloy Package Contents: 1 * flywheel 1 * locking ring Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.