Sram: Designed for the next generation of drivetrains—and the next generation of riders. The SRAM Force® XG-1270 cassette is optimized for electronic shifting and features our X-Range™ gearing technology. Smooth, precise shifts, from 10T on up.THINGS TO REMEMBERFeatures at least five one-tooth jumps for a smoother gear progression10-tooth start helps provide a wider gearing rangeDesigned to work with an XDR™ driver bodyMINI CLUSTER™ construction reduces weight and increases durabilityAll Zipp wheels starting from 2012 are XDR™ ready SPECIFICATIONSSpeed (CS): 12sGearing: 10-26t, 10-28t, 10-33tCog finish (Cassette): BlackTechnology (Cassette): XGCog sizes: 10-26t, 10-28t, 10-33t