1. This mountain bike rear derailleur converter, also known as a bicycle frame hanger, is designed specifically for mountain bikes and can effectively expand the functions of the frame. It is made of aluminum material. This material is not only lightweight, which can reduce unnecessary weight for the whole bike and make cycling easier, but also has good durability and corrosion resistance. It can adapt to various complex cycling environments and is not easily damaged even after long - term use. 2. The converter features an extended seat design, which can effectively extend the flywheel. Using it can optimize the bike's transmission system and improve the accuracy and smoothness of gear shifting. This allows cyclists to quickly and accurately complete gear - shifting operations on different road conditions and enjoy a smoother cycling experience. 3. In terms of specifications, its model is L23A, which has good compatibility and can be perfectly adapted to various types of mountain bike frames. Riders from different regions such as Africa, Europe, South America, Southeast Asia, North America, Northeast Asia, or the Middle East can use this frame hanger to enhance the performance of their mountain bikes.