SRAM designed the XX Rear Derailleur specifically to go with SRAM"s new top-end 2x10 mountain drivetrain. Exact Actuation Technology ensures that the XX Rear Derailleur moves exactly 3mm with each click of the shifter so you have perfect shifting every time. The carbon fiber cage keeps the weight down and flexes (instead of bending) when it takes a hit. Other details, like a titanium main spring, a forged magnesium inner link, and sealed ceramic pulleys push the XX Rear Derailleur to a level of sophistication unheard of until now.Product FeaturesMaterial: Aluminum, carbon fiber, magnesiumSpeeds: 10Cage: MediumTop / Low Normal:Maximum Front Difference: Total Capacity: 36TWeight: 181gRecommended Use: Changing gearsManufacturer Warranty: 2 Years