SRAM NX Eagle 12sp Rear DerailleurAs seen on the top-of-the-line XX1 and X01 models, the NX Eagle rear derailleur also adopts SRAM's 1x specific X-Horizon cage design. This carefully engineered mechanism ensures capacity for the huge 11-50T cassette and compliments the smooth Performance of an Eagle 12 speed system. This derailleur also boasts SRAM's Type-3 Roller Bearing Clutch for unrivalled durability and quiet consistent performance. Features:  Material: Aluminium (cage), Steel (spring, pulley), Stainless Steel (hardware)  Max Tooth: 50T  Compatibility: All Eagle drivetrains  Speeds: 12 Speed  Compatibility: 1x12  Max Tooth: 50  Pulleys: X-Sync  Pull: X-Actuation  Technology Highlights: X-Horizon, X-Actuation, X-Sync 2, Roller Bearing Clutch, Cage Lock  Weight: 339gTechnologies  X-Horizon: The X-Horizon 'straight parallelogram' design limits all movement on the horizontal axis, which makes ghost shifting impossible while also reducing shift force. The large upper pulley offset design maintains a constant chain gap across all gears and guarantees faster and more exact shifting.  X-Actuation: Developed specifically for SRAM 1x drivetrains, X-Actuation keeps shifting sharp and consistent across the entyre cassette. This makes gears easy to index and provides exceptional performance.    X-Sync 2: X-Sync 2 Eagle is the next evolution of SRAM X-Sync technology. The aggressive tooth design provides better chain retention for a smoother, more efficient pedal feel. With a focus on long wear-life, the X-Sync Eagle design reduces friction and the accumulation of mud, grit and grime.  Roller Bearing Clutch: The Roller Bearing Clutch delivers maximum drivetrain stability even through the most punishing terrain. This stability benefits the drivetrain dramatically, as derailleur bounce and chain slap are eliminated without sacrificing precision  Cage Lock: With Cage Lock technology in the rear derailleur, wheel removal and installation, as well as chain installation, becomes faster and simpler. Just push the cage forward to create slack and lock it into placeBuy SRAM Components from Chain Reaction Cycles, the World's Largest Online Bike Store.