Sram: Take a quick look at the new X-DOME™ Eagle™ cassette. The last dangling shred of an argument in favor of a mountain bike front derailleur is now officially dead. Designed for use with our proven, reliable XD™ Driver Body, this 12-speed, 10- to 50-tooth cassette offers an optimal 500-percent gear range at a considerably lighter weight than 2x systems. It carries with it the X-DOME™ architecture, which, independent tests have concluded, yields the strongest cassettes on the market. New shifting characteristics improve both, inboard and outboard shifting, as well as chain retention.