Rotor Q-Rings chainring, 9000/6800 4-arm 110 36 black: Specific to Shimano 9000/6800 4x110mm BCD cranks (outer rings include spider finishing caps for a clean look)Q-Ring's 10% ovalization offers a scientifically proven biomechanical advantage over round chainringsBest suited for long-distance riding and those who commonly spin while in the saddleOptimum Chainring Position power tuning feature: 5 OCP settings (outer)Made in Spain from CNC machined 7075-T6 aluminum with steel pinsAerodynamic shape also adds stiffness