1. DERAILLEUR HANGER: This CNC machined derailleur hanger is specifically designed for UDH compatible mountain bikes, incorporating thousands of mountain bike derailleur standards to compatibility with your bicycle's gear system. 2. INNOVATIVE SAFETY DESIGN: Engineered to rotate backwards during impacts, this derailleur hanger helps prevent damage to your bicycle frame while also featuring the ability to reinstall the chain onto the pinion automatically after mishaps. 3. CONSTRUCTION: Crafted from lightweight yet magnesium alloy with CNC manufacturing, this tail hook weighs only 31.28g while providing exceptional strength and reliability for your mountain biking adventures. 4. WIDE COMPATIBILITY: Compatible with all commercially available drivetrains and Ebike systems, this derailleur hanger seamlessly integrates with various gear systems while maintaining the AX12*P1.0 original shaft specifications.