Designed for the proven Xd Driver Body, this cassette features twelve sprockets with ten to fifty teeth and a total gear ratio of 500 percent. It is significantly lighter than two chainring setups. Independent tests show that its X-Dome construction makes it the most torsionally rigid cassette on the market. Its new features optimize both the shifting process and chain tension. The X-Dome technology results in an incredibly lightweight, precise, and robust cassette. The open design better sheds dirt and provides smoother shifting performance as well as longer component lifespan.