Exquisite Workmanship: The Bike Rear Derailleur Hanger Transmission Tail Hook adopts professional manufacturing and CNC technology, which has high reliability and makes flywheel speed expansion change more smoothly. Scope of Applications: The bicycle transmission tail hook is suitable for mountain road bike of 40T/42T/46T/50T/56T, which is an excellent accessory for cyclist. Bright Color: The bike rear derailleur extension tail hook provides bright color to make your mountain bike to be more personalized, and it is available in 2 colors to meet your different needs and requirements. Premium Quality: This brand new rear derailleur extension tail hook is made of high quality aluminium alloy material, which is sturdy and It is not easy to break, has quality and long service life. Product Specification: Item type: rear derailleur extension tail hook; model: YC-02; material: aluminium alloy; optional color: black, red; weight: approx. 20g.