Slim and tucked away is the name of the game with the Shimano Deore M610 rear derailleur. The medium cage length means you're not left with your cage hanging unnecessarily close to the rocks and logs you're clearing. Able to handle a 36 tooth ring in the back and an 18 tooth gear spread in the front, you can still run your huge cassette with ease. The Shadow design lets the cage of the derailleur sit tucked away under the cassette rather than poking out where an errant stick or rock can easily take it out. This plus the more efficient and lighter weight medium cage makes this derailleur ready for anything!