Shimano's Alivio Rear Derailleur is built to withstand the rigors of off-road riding, with a lightweight aluminum body and low-friction pivots for incredibly easy and smooth shifting. And, the Alivio features 11-tooth pulleys, which alternate chain-link contact reducing wear and smoothing pedaling. SPECS: Largest Cog: 34 Rear Derailleur Mount Type: 10x1 Standard Chain Wrap Capacity (teeth): 45 Cage Length: Long Rear Der/Shifter Compatibility: Shimano Mountain Drivetrain Speeds: 9