The Shimano Altus Shadow M2000 9 Speed Rear Derailleur offers riders precise, smooth and reliable shifting over varied terrain thanks to. With its unique 'Shadow' clutch derailleur system, you'll find that dropped and caught chains practically become a thing of the past. While its super low profile, lightweight design belies its rugged toughness. The unique tension spring makes it easy to remove your rear wheel and the cable adjuster ensures your drivetrain is always singing. The Shimano Altus Shadow M2000 9 Speed Rear Derailleur is the ideal rear derailleur for general cycling, off-road use and everything in between.