1、The bicycle flywheel is made of high strength steel nickel plated, using hardening technology, has greater wear resistance, durability, high temperature resistance, corrosion resistance, rust prevention, no deformation, good impact resistance. 2、Provides fast and accurate indexing conversion function through special tooth profiles and slope. Lost tooth design, irregularly shaped and irregular cut angle tooth profiles, better compatible with various brands of gear shifting chains, and shifts and shifts flexibly and smoothly. 3、The hollow design can easily reduce the weight of the bicycle, reduce the burden of riding, and achieve a good balance between strength and weight. It is easy to install and use. It is an ideal choice for reducing the weight of the bicycle. 4、Easy to install, professional manufacturing, direct replacement of old or damaged flywheels, excellent accessories for mountain bikes and road bikes, easy to install, without any adjustment to the transmission system, and can well control the transmission function. 5、Independent small tooth rings, the small teeth of the bicycle cassette flywheel are often used during use, and the independent small tooth design is convenient for future replacement and maintenance. High accuracy tooth profiles, strong compatibility. Item Type: Bike Cassette Material: Nickel Plated Steel Product Size: Approx. 170mm/6.7in  Diameter Speed: 11 Speed Number of Gear Teeth: 11-13-15-17-19-21-24-28-32-36-42T 1 x Bicycle Flywheel 2 x Sprocket 1 x Lock Ring