Featured in the 2016 DIRT 100 ‘Best trail/enduro transmission 2016’ Offering the best in shifting performance and reliability the SRAM XX1 – Type 2.1, is the ideal rear derailleur for trail and enduro mountain bikes. Precise shifting The SRAM XX1 rear mech features the X-horizon horizontal parallelogram design with offset pulleys that keeps a constant chain gap across all 11 gears. This limits all movement to the horizontal access which reduces shift force for fast, precise shifting. Ghost shifting is also eliminated. Roller bearing clutch Reducing chain bounce and slap the clutch mechanism helps to keep the chain in place as well as offering a quieter ride. Cage lock technology also makes wheel changes a lot easier. Key Features: Large upper pulley offset automatically adjusts chain gapX-Horizon design reduces shift force and ghost shifting12-tooth X-Sync pulley wheelsType 2.1 technologies: Roller Bearing Clutch and Cage LockHorizontal Parallelogram designNew silent pulley tooth designWeight: 245gColours: Red, BlackCompatibility: 1x11 X-ACTUATION™Bearings: BLACKBOX™ ceramic bearing pulleysCage Size: LongMax cassette tooth: 42t