The shimano ultegra rd 6870 di2 11 speed rear derailleur creates an amazing shifting action thanks to the di2 technology that brings the ultegra range into the next generation with super precise and easy to use shifting you will be left wondering why you never made the switch earlier once you use the ultegra 6870 with programmed automatic motion with the simple flick of a switch the 6870 rear derailleur creates not only a super quick shifting action but also one that is smooth and effort