A. These compatible gears, sprockets, and chainwheels are specifically designed for the engines of all - terrain vehicles, off - road motorcycles, and go - karts. They feature a delicate design that can provide stable and efficient support for the vehicle's power transmission. B. The model number is 520, which has high versatility in vehicle compatibility. It can be easily applied to various relevant vehicles. The matching relationship is quite suitable, enabling it to seamlessly integrate into the vehicle's overall system and ensuring that the engine's power can be smoothly transmitted to the wheels, thereby improving the vehicle's overall performance. C. There are multiple specifications available, including 520 - 10T gears, 520 - 11T gears, 520 - 12T gears, 520 - 13T gears, 520 - 14T gears, 520 - 15T gears, 520 - 16T gears, 520 - 17T gears, 520 - 18T gears, 520 - 19T gears, 520 - 20T gears, 520 - 22T gears, etc. These diverse options can meet different user needs. Whether you are a racing enthusiast seeking high - performance or an ordinary user for daily use, you can find a suitable specification for your vehicle. D. This product is sold in regions such as Africa, Europe, South America, Southeast Asia, North America, Northeast Asia, and the Middle East and has gained wide recognition. It is a good choice for improving vehicle performance.