The workhorse of X-Range™ gearing. The SRAM RED® XG-1290 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.Key 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,.Specifications:Speed (CS): 12sGearing: 10-26t, 10-28t, 10-33tCog finish (Cassette): SilverTechnology (Cassette): XGCog 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