1、High Quality Material: The bike rear derailleur extenderis made of quality aluminum alloy with CNC machining, sturdy and firm, durable and corrosion resistant. 2、Stable Performance: The bike rear derailleur hanger makes the flywheel speed change more smoothly. It also makes your riding smoother and provides a good riding experience. 3、Application: The bike rear derailleur extension is used to lengthen the rear dial chain, and apply to mountain or road bike modification with 34-52T large flywheel. 4、Lightweight: This frame gear tail hook extender only weighs 22g / 0.78oz, it is very light and portable. You can take it with you at any time, and you can directly replace it when it is convenient. 5、Great Accessory: The bike alloy rear derailleur hanger is a great accessory for cycling enthusiasts. Bright colors to give your mountain bike more personality.