Specification: Item Type: Rear Derailleur Hanger Extension Material: Aluminum Alloy Screw Material: Aluminum Alloy 'aluminum Process: CNC precision machining, aluminum alloy anodizing surface Size: approx. 4.5cm / 1.8inch ID: approx. 1.6 cm / 0.6 inch Fitment: For upgrading 8-speed, 9-speed, 10-speed, 11-speed and 12-speed large flywheel teeth Color Black Item weight 13 Grams About this item STRONG AND STURDY: The rear derailleur extender is made of aluminum alloy. high quality aluminum, which is durable, not easy to rust and has a long service life, so the rear derailleur hanger can be purchased and used with confidence CNC PRECISE MACHINING: The bracket The bicycle rear derailleur has aluminum alloy anode color screws at the rear, easy to install and remove, and can be replaced quickly. Without complicated steps and tools, and has good texture, smooth surface and practicality STABLE SPEED: Bike tail hook with the function of widening the flywheel to make shifting more stable , great accessory for cyclists.The bicycle rear derailleur hanger is equipped with good protection, which can prevent the bicycle from falling and being damaged REDUCE SPRING TENSION: With this mountain bike rear derailleur hanger, relieve rear derailleur spring tension and no longer worry about climbing HIGH COMPATIBILITY: Our bike rear hanger is suitable for most types of bicycles, and the old tailstock can be replaced, which is more cost-effective than buying a new bike and reduces frame maintenance costs