Many feel that the SRAM XX Cassette is the centerpiece of the XX group. It is an impressive feat of machining -- spin the cogset and the design is mesmerizing. Spin it on an acid trip and you'll be smiling in awe for hours.SRAM once again borrowed an idea from their Red road group when they started designing this cassette. The Red PowerDome is a cassette machined out of a single piece of steel. Steel. And it's still lighter than just about every road cassette out there. The only problem with this design is that it can easily get jammed with dirt, a fact not lost on SRAM-equipped cyclocrossers, who run SRAM's less-expensive cassettes. So SRAM started with the basic idea, machined steel will be stronger, more durable, and lighter, and re-conceived the idea as X-Dome. X-Dome has eight of the ten cogs in a single body -- that's a lot of CNC-machining of a single block of steel. In fact, it takes nine hours of machining to get it to the skeletal minimum. The aluminum large cog in back is press-fit onto the block of eight and is replaceable. The tenth cog is the smallest one, and is made of steel as well.The SRAM XX cassette comes with ten cogs. Nine are made of 4130 chromoly steel. The tenth (largest) is made from 7075-T6 aluminum and is individually replaceable. The lock ring is made from 7075-T6 aluminum as well. The shifting cutouts and ramps are X-glide. SRAM recommends using their 1090 or 1090R chain with this cassette, though any 10-speed chain is compatible. Claimed weight of the SRAM XX Cassette in the 11/32 ratio is 185g, in 11/36 ratio is 208g. Choose between two gearing options:The 11/32 includes: 11,12,14,16,18,20,22,25,28,32The 11/36 includes: 11,12,14,16,18,21,24,28,32,36Click here to save when you purchase an XX build kit.