The SRAM X01 Eagle Rear Derailleur features an updated cage architecture to provide better chain management.Features-Type 3 clutch is smoother and more durable-14T lower pulley- Includes a chain gap tool that makes it easy to set up the correct chain length-Designed for a max 52t large cogItem Specifications-Rear Derailleur Mount Type:10x1 Standard-Drivetrain Speeds:12-Color:Red-Chain Wrap Capacity (teeth):42 teeth-Cage Length:Long-Largest Cog:52-Rear Der/Shifter Compatibility:SRAM X-Actuation