The Turbine Rings are the product of 2 years of engineering and testing on Canada"s brutal North Shore trails.CNC machined AL7075-T6 in British Columbia, CanadaSpecific architecture for for Race Face, Shimano or Truvativ tabsThree times stiffer than Team rings with greater impact resistance9speed compatible; include outer chainring boltsMore upshift and downshift zones than Race Face Team ringsItem SpecificationsColorBlackMaterialAL7075Teeth22,32,44teethBolt Pattern4-BoltChainring BCD104,64mmRing PositionInner,Middle,OuterChain Compatibility9-SpeedDefined ColorBlack