Quarq: FEATURESAXS™ enabled for easy monitoring and firmware upgradesX-Range™ gearing technology gives you more range and a smoother gear progression, so you're always in the right gearIntegrated power measurementPower meter is fully integrated into the chainring set for lighter weightPower readings are accurate within +/-1.5% and aren't affected by climate conditions during a ridePower balance measures left and right legs separatelyImproved front shifting performance for crisp and accurate front shiftsUnique chainring shape results in a lighter weight, stiffer, more durable cranksetIntegrated chainring design significantly reduces weight8-bolt direct mount compatibility only to new RED® and Force eTap AXS™ cranks. Not reverse compatible with prior 8-bolt cranks SPECIFICATIONSSpeeds: 12Crank arm length: n/aBB Compatibility: n/aChainring Size: 52/39T, 54/41T, 56/43TBolt Circle Diameter (BCD): Direct Mount (DM)Chainline: n/aBB Spindle Interface: n/aChainring material: AluminumGuard: n/aCrank arm material: n/aColor (Crank arm): n/aPower Meter Type: Ant USBHub Spacing Compatibility: Standard 142mm