The Shimano Deore XT RD-M8200 is a 12-speed mechanical rear derailleur built around trail durability. SHADOW ES delivers a slimmer, stronger chain stabilizer with a wide link structure, and a wedge-shaped low-profile body helps the derailleur move out of the way on impact rather than take the hit directly. What Our Gearhead(R) Experts Are Saying:"The wedge shape and internal spring absorb trail hits and return to position without skipping a beat. For enduro and all-mountain riding where rock strikes are a matter of when, not if, that's the detail that keeps the drivetrain running."