1. This is a multi-functional bicycle extension rack made of aluminum alloy. It has good durability and stability, bringing you many conveniences during cycling. 2. This extension rack can be used as an expansion frame for devices such as bicycle lights and cycling computers, adding more functions to your bicycle. Its model is C71, and it can fit most common bicycles. 3. Whether it is a daily commuting bicycle, a professional mountain bike, or a road bike, it can be installed well. You can easily install a bicycle light, a cycling computer, etc. on this extension rack, making it more convenient for you to get lighting and check data while cycling. 4. With it, you don't have to worry about not finding a suitable installation position, which greatly improves your cycling experience.