If you value reliable gear changes and low weight, the Shimano RD-6800 Ultegra 2-Speed Rear derailleur is the thing for you. The rear derailleur is relatively light and boasts excellent features that facilitate shifting. The nifty spring mechanism allows for quick and precise gear changes and will keep the switching forces consistent. Plus, the rear derailleur is easy to adjust and will stay that way so that you dont have to adjust it repeatedly. As a result of the stiffness, changing gears when riding out of the saddle is very precise and seamless. Avid road cyclists will love the Shimano RD-6800 Ultegra 2-Speed Rear derailleur!