1. The chain has good fit and operates more smoothly 2. The deep tooth pattern design effectively reduces chain breakage, provides a crisp shifting mechanism, and ensures a more stable chain engagement 3. The aluminum alloy body with a hollow design is lighter in weight and has better wear resistance 4. The aluminum alloy bicycle drive wheels contain polyurethane, offering lightweight, smooth, low-resistance transmission, stability, wear resistance, and rust resistance, making it suitable for a wide range of applications with a long lifespan 5. Materials: aluminum body + metal polyurethane 6. Size: 11T: about 4.5 x 1 cm; 13T: about 5 x 1 cm
