1The bicycle flywheel is made of high strength steel nickel plated and adopts hardening technology, which has greater wear resistance, durability, high temperature resistance, corrosion resistance, rust resistance, and no deformation. 2High durability, good impact resistance, high accuracy tooth shape, toothless design, and strong customerability, which makes riding more possible, unique mountain bike chain design, which can well control the shifting function. 3Provides fast and accurate indexing conversion function through special tooth shape and slope, lost tooth design, special shaped irregular cut angle tooth shape, better compatible with various brands of transmission chains, shifting and shifting speed is agile and smooth. 4The hollow design can easily reduce weight, reduce the burden of riding, and achieve a good balance between strength and weigh, reinforced aluminum frame, all over the mud holes, effective speed change, easy to install and use, it is an ideal choice for reducing the weight of the bicycle. 5Easy to install, 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 shifting system. 6The independent small tooth ring, 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 Freewheel Material: Main Body Steel Nickel Plated + Aluminum Alloy Frame (Red) Product Size: Diameter Approx. 203mm/7.9in Speed: 10 Speed Number of Gear Teeth: 11-13-15-18-21-24-30-36-42-50T 1 x Bicycle Flywheel 2 x Sprocket 1 x LockRing Manual measurement allows error