The SRAM XS-1299 XX SL Eagle Transmission 12-Speed Cassette has been engineered to be the lightest cassette SRAM has ever created and delivers us peak shifting performance. Built with a full X-SYNC design to truly shift better the harder we pedal, this cassette offers a 520% gear range so that we can keep the pedals spinning no matter how steep the trail gets. The new Eagle Transmission system delivers precise, smooth shifting every single time thanks to the direct contact between our derailleur and cassette, while the hardened steel X-Dome for the 10 to 32-tooth cogs is fully-machined to be durable and long-lasting so we can spend more time riding and less time working on bikes.