Sram RIVAL-1 11-Speed Rear Derailleur Long BlackYour needs aren't less demanding, they're different. The SRAM Rival 1 rear derailleur is engineered for smooth, reliable shifting action, delivering 100% of what you demand. By eliminating unwanted chain movement, X HORIZON shifts faster, reducing shift effort and chain slap. A dedicated SRAM 1x rear derailleur Exact Actuation for fast and accurate shifts using SRAM's 1: 1 actuation ratio (shifter cable travel : derailleur movement) X Sync pulley