1、Fast and accurate with special tooth shape and tilt, lost tooth design, specially shaped irregular cutting angle tooth shape, compatibility with various brands of gear shift chains, and flexible and smooth shifts and shifts, provides index conversion function. 2、The hollow design makes it easy to reduce weight, reduce the burden of riding and balance strength and weight. reinforced aluminum frame, entire mud hole, effective speed change, all easy to install and use, ideal choices such as, reduce the weight of your bike. 3、Easy to install, professionally manufactured, direct replacement of old or damaged flywheels, excellent accessories for mountain and road bikes that are easy to install without adjusting the shift system, unique with proper control of shift function mountain bike chain design. 4、Independent small tooth ring, small teeth of bicycle cassette flywheel are often used in use, independent small tooth design is convenient for future replacement and maintenance, due to high tooth shape accuracy, gearless design, and strong compatibility , allows you to ride more. 5、The flywheel of the bicycle is made of high strength steel nickel plating using hardening technology, which provides wear resistance, durability, high temperature resistance, corrosion resistance, rust resistance, no deformation, high hardening resistance, and excellent impact resistance. Item Type: Bike Freewheel Material: Steel Nickel Plated Product Size: Diameter Approx. 170mm/6.6in Speed: 10 Speed Number of Gear Teeth: 11-13-15-18-21-24-28-32-36-42T 1 x Bicycle Flywheel 2 x Sprocket 1 x Lock Ring