Features: The high performances designs of folding bike single speed flywheel provide fast cycling speed while saving effort. Mountain bike single speed flywheel have smooth turn action no much noise. Make of aluminum alloys, strong, Rusts resistant and wear resistant. It have high accuracy thread machining to ensures a tight connection with the bike wheel andsilky running. It can directly replaces old and broken accessories, ensuring the normal of your bike. Specifications: Materials: Aluminum alloy Color: Redness/Black/Blue/Purpleness Styles: 18T Size: as shown in the picture Package Includes: 1set Single Speed Flywheel note: Please allow 1-2cm errors due to manual measurement, make surely that you not mind before order. Due to difference between different monitors, the picture may not reflect the actual color. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.