XTR Di 2 Dyna-Sys 11-speed front derailleurs operation is pioneering smooth shifting is guaranteed thanks to a microchip communication link with the gear levers. Whats more shifting the rear derailleur automatically trims the front derailleur Shimano FD-M9050 XTR Di 2 requires SMFD905 mount The biggest difference you will notice is just how much quicker & effortlessly smoother shifting on the front chainrings is even under load The difference in the effort & time to actuate the shift between mechanical & Di 2 is truly staggering The removal of traditional mechanical cables in favour of electrical wires not only eliminates poor shifting caused by contaminates corrosion & stretching but provides effortless gear shifts no matter what the conditions The front derailleur also trims automatically; the cage moves in response to the position of the rear derailleur on the cassette to ensure no chain rub & a quiet unobtrusive ride enabling you to concentrate on the trail ahead Synchro shift compatible meaning a single shifter can control both front & rear shifting which can be fully custom tuned to your riding preferences Braze-on fit as standard; Modular mounting means that you can choose from a range of mounting options to cater for all frame designs 11-speed E-tube Di 2 compatible Triple compatible for 40T