Precision engineered XTR Shadow Dyna-Sys 10-speed rear derailleur for the ultimate in shifting performance & durability Shadow features a super low profile design that reduces the risk of damage from trail side hazards Single tension spring prevents contact with the chainstay resulting in a silent ride Direct cable routing prevents snagging from any trail side hazards Full carbon fibre outer pulley cage saves weight while alloy inner cage increases rigidity Cold forged alloy links & pivot bodys with carbon composite P-body leads to lower weight without compromising strength & durability Four fluorine-coated link pin bushings make this one of the slickest shifting derailleurs on the trails High rigidity wide outer link braces the pulley body to increase pivot joint rigidity resulting in a crisp shift Strong return spring for a positive shifting feel Improved cable pull ratio provides a more accurate shift action making the system less prone to contamination & trail chatter Dyna-Sys 10-speed compatible only Durable sealed bearing pulleys for low friction Top normal spring uses the spring to select higher gears 41T capacity SGS cage Weight 177 grams