Sram: Sometimes all you need is a fresh coat of paint. With revised graphics to match SRAM RED eTap components, the PowerdomeX™ is still the most advanced cassette ever made. It's super light, deadly silent, and delivers an undeniable performance advantage. The nine cogs in the cog cluster are machined from a single block of high grade tool steel, increasing stiffness while weighing even less than a titanium cassette. Between each cog is a StealthRing™ elastomer to reduce vibration and noise. Cutouts on the rear cog further reduce weight and add stiffness. It's the final piece in the drivetrain puzzle, and paired with the new SRAM Red rear derailleur, it delivers ultra-fast, ultra-quiet shifts that will always put you in the right gear.Heat-treated, high-grade tool steel provides superlative durability and a beautiful finishStealthRing™ elastomers and advanced tooth profiles eliminate vibration and noise for a smooth, silent rideAluminum cog: lighter, stiffer, stronger due to the design, material and production processISO 4210 compliant - see declaration of conformity for details