The SRAM RED XG-1290 12-Speed Cassette progresses fluidly and quickly through a wider range of gears. It’s specifically designed for wireless electronic shifting and the one-piece design offers you the best in weight savings. SRAM RED XG-1290 12-Speed Cassette Features Updated design for smoother and faster shifting More gradual gear progression between cogs—at least five one-tooth jumps—while still offering a wider range 10-tooth start helps provide a wider gearing range Designed to work with an XDR™ driver body One-piece machined steel X-Dome™ design for weight savings All Zipp wheels starting from 2012 are XDR™ ready Speed (CS): 12s Gearing: 10-26t, 10-28t, 10-33t Cog finish (Cassette): Silver Technology (Cassette): XG Cog sizes: 10-26t;10,11,12,13,14,15,16,17,19,21,23,26, 10-28t;10,11,12,13,14,15,16,17,19,21,24,28, 10-33t;10,11,12,13,14,15,17,19,21,24,28,33