MAXIMUM IMPACT With its "horizontal parallelogram" design and signature roller spacing, X-HORIZON™ maintains consistent chain blur through all 11 gears, providing fast and accurate shifting. By limiting all movement to the horizontal axis, this design provides more speed, reduces shifting force and eliminates unintended shifting problems. ROLLER BEARING CLUTCH™ technology reduces rebound and prevents the chain from banging too often. CAGE LOCK™ technology makes it easier than ever to remove and install wheels. Combined with the XX1 shifter, the X-HORIZON rear derailleur is the centerpiece of X-ACTUATION™ technology for incredibly smooth shifting. Wide top roller spacing automatically adjusts chain slack Straight parallelogram design with horizontal movement reduces shifting force and improves drivetrain performance X-SYNC 12-Tooth rollers (1 in 2 teeth is square) TYPE 2 technologies: ROLLER BEARING CLUTCH™ and CAGE LOCK™. New quiet tooth rollers. Verified weight: 261 g