Shimano XTR M9250 Di2 Upkit - Rear Derailer and ShifterShimano XTR M9250 Di2 Upkit Rear Derailler and Shifter The all new XTR M9250 long cage derailleur paired with a standard 10 51T M9200 cassette gives riders and racers the speed, range, and robustness to tackle every trail on the mountain. With built in Automatic Impact Recovery, an impact deflecting shape, and simple covered pulley solutions, this derailleur stands up to harsh trail impacts and still retains its lightning quick shifting speed and top