A. This bicycle fork steerer tube expansion plug, also known as the sunflower expansion plug, is made of good-quality aluminum material. Aluminum is strong, durable, and lightweight, which can effectively reduce the overall burden of the bicycle and make cycling easier. B. It is suitable for mountain bikes and road bikes, making it a good choice for cycling enthusiasts. Whether you are cycling on rough mountain trails or speeding on flat roads, this expansion plug can provide stable support for your ride. C. Its specification model is S26TCR and it has good adaptability. It can precisely match bicycles of the corresponding specifications, and the installation process is simple and convenient, so you don't need to worry about the installation. D. With its decent aluminum material and good adaptability, this fork steerer tube expansion plug will significantly enhance your cycling experience.