Feature: 1. Made of high‑strength steel tempering and quenching process, it has higher strength, durability and strong wear resistance. 2. It has strong oxidation resistance, is not easy to rust, and has a long service life, so it can be used with confidence. 3. With a hollow design, the weight is reduced, and it will not add too much burden to your bicycle when using it. 4. The surface adopts chrome plating technology, and the sliver surface has a delicate appearance. 5. Professional manufacturing, it can directly replace your old or broken freewheel. Wonderful accessory for mountain bike and road cycling. Specification: Item Type: Freewheel Cassette Gear Material: Chrome Molybdenum Steel Product Color: Black and Silver Product Weight: Approx. 702g / 24.8oz Gear Ratio: 11-46T (11-13-15-18-21-24-28-32-36-42-46T). Package List: 1 x Flywheel2 x Sprocket1 x Flywheel Cover Note: After the installation is complete, check whether the flywheel is locked and whether it is aligned.