The revolutionary machined design of the sram xx 10 speed cassette uses the same gruelling manufacturing techniques that produced the powerdome road cassette with x dome eight of the cogs are cnc machined together out of a single block of billet steel creating an incredibly lightweight precise and strong cassette the process takes 9 hours per cassette you have never seen a cassette that looks like this the open design aids in mud clearance giving you cleaner shifting performance and long