The MTB Derailleur Hanger Extension Bike is made of aluminum alloy material, durable and anti-corrosion, can be used for a long time. Sturdy and durableRear Derailleur Gearbox Extender is made of aluminum alloy, weighs 12 grams, has a total length of 44 mm and a thickness of 11.5 mm. Easy to carry. The Bicycle Extender Tail Hook Frame uses fine workmanship to achieve the perfect finish. The surface is anodized, anti-corrosion and anti-rust, so as to ensure long-term use. Easy to Install The installation of MTB Gearbox Extension is very simple, just replace the screw that secures the rear derailleur to the bike board. Simple and convenient, save time and effort. Ideal AccessoryRear Derailleur Adapter allows you to change the speed of the flywheel more smoothly and is a great accessory for cyclists. Widely used Rear Derailleur Extension is suitable for 40T or 42T or 46T or 50T mountain flywheels or 32T or 36T road flywheels, making the flywheel expansion smoother Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.