Features1Stable and Secure: The unique radiation type anti loosening pressure groove effectively prevents screw from loosening during use by uniformly applying force at multiple points, ensuring that the bike frame extender and rear extension mount remain stable during strenuous movement 2Flexible Adjustment: Provides multiple gears adjustment, allowing you to easily adjust the position of the tail hook and flywheel according to different bike model and riding styles, meeting personalized installation needs, optimizing chain tension and transmissing system performance 3Anodized Coating: Adopting anodizing technology, not only does it coat the finish of the product with a sturdy and lasting protective film, but it also brings bright colors, scratch resisting and wear resisting, and can maintain a bright color even after long term exposure to outdoor environments 4Aluminum Alloy: The rear hook extension is made of aluminum alloy material, with fine processing, ensuring strength while significantly reducing weight and load, making each step light and more efficient, making it suitable for various complex terrains 5Easy Installation: This bike frame tail hook extension features a standardized interface design that allows for quick installation and removal without the need for professional tools. Even novice riders can easily upgrade their bikes, greatly improving performanceSpecificationItem Type: Bike Tail Hook ExtenderProduct Material: Aluminium AlloyPackage List1 x Rear Hook Extender1 x Screw