Virtually silent compared to the discordant reverberation produced by SRAM's original Red Cassette, the SRAM XG 1190 Cassette is engineered to complement SRAM's Red 22 groupset. Its StealthRing elastomers fitted between each cog eliminate the harsh drivetrain noise found on the previous incarnation, absorbing excess chatter by dampening chain vibration. This beautiful crafted cassette uses heat treated, high grade tool steel for its middle nine cogs. Two machined aluminum cogs are placed at the upper and lower gears, with the largest cog featuring a machined backplate to increase stiffness and strength when you're punching up steep grades. Note that this cassette only fits 11 speed compatible hubfreehub bodies, and SRAM recommends pairing with its PC RED 22 chain for optimal shifting and reduced drivetrain noise.