Description: Material: Carbon steel wear-resistant front derailleur is accurate and direct and the speed change is sensitive and fast. Aluminum alloy rear derailleur is lightweight and high strength long-leg guide plate design. ABS guide wheels are silent and smooth, can reduce chain wear.Extended three-finger handle: The derailleur handle adopts a three-finger lengthened design and the three-finger grip is accurate and compact.Clear digital gear dial: There is a clear digital gear dial in the middle which makes the gear shift correct and more intuitive.What You Get: You can get 1pc left thumb derailleur, 1pc right thumb derailleur, 1pc front dial, 1pc back dial.Brake speed tandem design: One-piece tandem design, braking and shifting effortlessly.Specifications: Product name: Bicycle DerailleurColor: BlackMaterial: Aluminum Alloy + ABS + Carbon SteelThumb Derailleur Size(L x W): About 18 x 10cm/ 7.1 x 3.9inchThumb Derailleur Cord Length: About 162cm/ 63.8inchFront Dial Size(Upper L x Bottom L x W): About 8.5 x 10 x 10cm/ 3.3 x 3.9 x 3.9inchBack Dial Size(L x W): About 14 x 8.5cm/ 5.5 x 3.3inchSuitable for: Handlebar diameter within 22.2mmSpeed Type: 21 speedPackage Includes: 1Pc x Left Thumb Derailleur1Pc x Right Thumb Derailleur1Pc x Front Dial1Pc x Back DialNote:1. Due to the screen difference, the item's color may be slightly different from the pictures.2. Please allow 0.5-2 cm differences due to manual measurement.