The SRAM NX X-HORIZON™ rear derailleur is designed to provide the same smooth, reliable shifting quality as the XX1, from the ideal spacing of the top roller with the cassette teeth to the 12-tooth X-SYNC™ rollers. By eliminating unwanted chain movement, X-HORIZON™ allows for faster and very smooth shifting from the lever, prevents unintentional shifting from one tooth to the next, and prevents the chain from banging on the rear chainstay too often. CAGE LOCK™ technology makes it easier than ever to remove and install the rear wheel. Features:X-HORIZON™ design increases shifting smoothness, while preventing unintentional shifting and the chain from banging on the rear chainstay too often 12-tooth X-SYNC™ rollers Fully compatible with all SRAM 1x™ drivetrains. The most affordable complete 1X rear derailleur in the industry Bearings: steel Weight: 322g