Now compatible with a wider range of cassette tooth count options, the Ultegra R8000 11 Speed Rear Derailleur delivers has been optimised by Shimano to offer fast and accurate gear shifts with minimal rider effort. In addition to the slick shifting, it also adopts the Shadow cage design to sit closer to your bike's frame. This improving its aerodynamics and protects it should you be unlucky enough to have a crash. Race-ready, it's made in two different cage sizes to suit your cassette size preference.