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