A. This bottom bracket crank cap is designed for mountain bikes and road bikes. It adopts the design concept of a hollow integrated structure, which can provide all-round protection for the BB bottom bracket XT crankset. B. This product comes in two specifications, M20 and M18. Different specifications can meet the needs of different bicycles, enabling precise adaptation to various types of bicycles and ensuring the stability and fit of the installation. C. In terms of quality, it is strictly controlled and has good dust and water resistance. It can effectively prevent dust, water stains, etc. from entering the inside of the crankset, reducing the wear and corrosion caused by dust and moisture to the crankset, extending the service life of the crankset, and ensuring the normal operation of the bicycle. D. Whether it's for daily riding, mountain exploration, or road racing, this bottom bracket crank cap can play an important role, safeguarding your cycling journey and being a good choice for bicycle accessories.