1. This single-speed chain tensioner for folding bicycles is made of aluminum alloy using CNC technology. As a chain adjuster and tensioner, it can effectively prevent the chain from falling off, ensuring a smooth and safe riding process. 2. The aluminum alloy material has many advantages. It is not only lightweight and does not add too much extra burden to the bicycle, making it easy to carry and operate. In addition, it has good durability and corrosion resistance, can withstand the test of different environments, and is not easy to damage even after long-term use. 3. The size of this chain tensioner is suitable for folding bicycles with a single-speed transmission system and can match the vehicle well, providing reliable support for riding. 4. Whether you are commuting daily, riding for leisure, or participating in other outdoor activities, it is a good accessory for folding bicycles and can make your riding experience more perfect.