A. This is an adapter tool called "Feizhou" for measuring the knee joint angle of road bicycles. It is specifically designed to optimize the cycling posture. B. It is made of a combination of plastic and metal, which is sturdy and durable, providing long - term and stable usage experience for cycling enthusiasts. The product is presented in a combined set to meet different usage needs. C. This knee joint angle measuring tool has relatively strong specification adaptability. It can accurately measure the knee joint angle, helping cyclists adjust to a more scientific and comfortable cycling posture, effectively reducing the risk of knee joint injury during cycling, and improving the comfort and efficiency of cycling. Both professional cyclists in training and ordinary cycling enthusiasts in daily rides can use it to optimize their cycling experience. D. It is widely applicable to cycling scenarios in multiple regions around the world, including Europe, South America, Southeast Asia, and North America. It can provide professional cycling posture adjustment services for cyclists. Meanwhile, for merchants engaged in cycling - related businesses on major mainstream e - commerce platforms, it is also a competitive product that can attract more cyclists' attention.