SRAM’s revolutionary PowerdomeX cassette gets a bit of a refresh to match SRAMs Redreg eTap aesthetics. Still offering amazingly precise shifting the XG-1190 is just as deadly silent and light as ever. The nine center cogs are machined from a single block of high-grade tool steel for a strong stiff and durable cassette that weighs even less than titanium. The largest cog is made of heat-treated aluminum with cutouts to reduce weight without compromising stiffness. In addition StealthRing elastomer inserts sandwiched between each sprocket cut way down on vibration and noise so the competition wont even hear it coming.