SRAM XG1299 10-52 12s XD BLACK EAGLE T-TYPENew gen design is Sram`s lightest ever 10 52T cassette due to the ultra lightweight, all aluminum Spider Cog Fully machined, hardened steel X Dome architecture for gears 1 9 and an ultra lightweight, all aluminum Spider Cog for gears 10 12 Full X SYNC for best ever inboard and outboard shifting performance under load with optimized gear steps on the low end 55mm chainline compatibility for more moderate chain angle, longer wear and greater precision