Features: Specially designed for bicycles enthusiasts and maintenance personnel. It makes the disassembly and assembly of bicycles wheels and chains from tedious to convenient. Accurately limit the position of the chain, ensuring stability and none deviation during disassembly, making the disassembly process smoother and easier for beginners to operate. Optimize the gear shifts positioning during wheel set disassembly, simplify the wheel set disassembly process, greatly save maintenance time, practical for outdoor emergencies or daily maintenance. It combines toughness and light weight characteristics, can be easily placed in seat cushions, tool bags, and carried around without any burden. The structure has been reinforced with design, and there is none risk of fracture under daily reasonable operate. Specifications: Component: Aluminum Alloy Size: about 7.3x2.3cm/2.87x0.91inch Suitable for the following mainstream transmission systems: For12 speed electronic transmission set; 9-10-11 speed mechanical rear shifts; 10-11-12 speed mechanical rear shifts; XT series, series mechanical rear shifts; 105 series mechanical rear dials. Package Includes: 1pc Bike Rear Derailleur shifts Retainer note: Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item.