The 10-speed X-Horizon rear derailleur makes shifting smooth and reliable no matter where you ride. Engineered to maintain consistent chain gap across all seven gears, X-Horizon eliminates vertical movement for faster shifting, reduced shift force and an end to ghost shifting. Roller Bearing Clutch technology and the 12-tooth X-Sync pulley wheels hold the chain in place, reducing bounce and chain slap. And Cage Lock technology makes wheel removal and installation easier than ever.   Features X-Horizon technology provides more responsive shifting and eliminates ghost shifting, a common problem on DH bikes. X-ACTUATION with more cable pull delivers optimized system performance and durability. Roller Bearing Clutch with Cage Lock sets the industry standard.   Specification Short Cage: 11-26T. Medium Cage: 11-32T.