A. This rear disc brake caliper lower pump is designed for all - terrain vehicles (ATVs), go - karts, and off - road vehicles with a displacement of 50 - 150cc. Its unique design allows it to fit the corresponding models well, providing precise and efficient braking support for the vehicles. It's a good option for vehicle modification. B. In terms of materials, it is made of semi - metallic materials. Semi - metallic materials have good wear resistance and stability, and can withstand high - intensity friction and pressure. They can ensure good braking performance under various complex road conditions and driving conditions, thus ensuring the safety of the driver. C. Whether on an exciting go - kart track or a challenging off - road journey, this brake caliper lower pump can play an important role, providing reliable support for the vehicle's braking system. D. It is an accessory that can improve the performance of 50 - 150cc all - terrain vehicles (ATVs), go - karts, and off - road vehicles, and is favored by users in regions such as Africa, Europe, South America, Southeast Asia, North America, Northeast Asia, and the Middle East.