1、Made of high strength steel nickel plated and aluminum alloy frame, using hardening technology, has greater wear resistance, durability, high temperature resistance, corrosion resistance, rust prevention, no deformation, good impact resistance. 2、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. Provides fast and accurate indexing conversion function through special tooth profiles and slope. 3、The hollow design can easily reduce weight, reduce the burden of riding, and achieve a good balance between strength and weight; reinforced aluminum frame, all over the mud hole, effective speed change; easy to install and use, it is an ideal choice to reduce the weight of the bicycle. 4、The unique mountain bike chain design can well control the speed change function. Professional manufacturing, direct replacement of old or damaged flywheels, excellent accessories for mountain bikes and road bikes, easy to install, without any adjustments to the transmission system. 5、High accuracy tooth profiles, strong compatibility. 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. Item Type: Bike Cassette Material: Main Body Steel Nickel Plated, Aluminum Alloy Frame (red) Product Size: Approx. 203mm/8.0in  Diameter Speed: 11 Speed Number of Gear Teeth: 11-13-15-18-21-24-28-32-36-42-50T 1 x Bicycle Flywheel 2 x Sprocket 1 x Lock Loop