Shimano's Deore XT Dyna-Sys 10-Speed Shadow Rear Derailleur is perfect for today's aggressive, all-mountain riding. The radical design means that the Shadow is super-low profile; it barely protrudes more than the quick release nut. Direct cable routing fires off shifts super quick and reduces the chance of the cable snagging on roots and rocks. A stronger spring keeps the body more stable when blasting through technical terrain at speed and yields a firm, crisp shifting feel. Plus, the bracket axle keeps the derailleur body from contacting your chainstay and reduces chatter so you just concentrate on the best line.