Material: Made of high-quality aluminum alloy, with smooth surface, firm structure, durability, abrasion resistance and long-term use Size: 2 x bicycle frame transmission gear tail hook replacement, with screws. 5.7 * 3.5cm /2.24x1.38 inches. Meet your use needs Effective protection: After being fixed on the rack, it can protect the transmission after dialing. It can protect your bike from being damaged when you fall Convenient installation: The upper end of the tail hook is connected with the frame, and the lower end is connected with the rear dial of the transmission. Simple operation and convenient use Wide application: Suitable for most types of mountain bikes and road bikes; Please compare the parts you need to replace to see if their sizes and shapes match