Sram: The XX SL Eagle Transmission (T-Type) Cassette is a major reason why Eagle Transmission offers the best-ever inboard and outboard shifting performance under load. Thanks to its full X-SYNC design, the harder you pedal, the better it shifts. Literally. Our lightest Eagle cassette in history lasts far longer and delivers more precision. Its new-gen design is fully machined, hardened steel X-Dome architecture for gears 1-9 and an ultra-lightweight, all-aluminum Spider Cog for gears 10-12. Engineered as integrated and interdependent transmission components, the XX Eagle Transmission Cassette and derailleur contact directly, ensuring perfect alignment on every bike. From its massive 520% gear range, the 52 tooth cog steps down with improved gear progression with 44 and 38 tooth cogs in the low end (compared to the Eagle drivetrain 10-52-tooth cassette). Featuring a clearly marked Setup Cog, install is both simple and fool-proof. FEATURES New-gen design is our lightest ever 10-52T cassette due to the ultra-lightweight, all-aluminum Spider Cog Full X-SYNC for best-ever inboard and outboard shifting performance under load. Optimized gear steps on low end 55mm chainline compatibility for more moderate chain angle, longer wear and greater precision. Setup Cog for fool-proof set up. Utilizes well accepted and broadly available XD driverbody SPECIFICATIONS Speed (CS): 12s Gearing: 10-52t Cog finish (Cassette): Black Technology (Cassette): XS Cog sizes: 10-52t:10,12,14,16,18,21,24,28,32,38,44,52 Driver body interface: XD