Rotor QXL chainring, compact 110 bcd 5 bolt black: Fits common compact 110mm BCD road cranks. QXL’s 16% ovalization is for riders seeking greater biomechanical advantage (ideal for riders who already have experience on Q-rings with 10% ovalization). Best suited for time-trials, sprints, and riders who frequently pedal out of the saddle. Optimum Chainring Position power tuning feature: 5 OCP settings (1,2,3,4,5). Made in Spain from CNC machined 7075-T6 aluminum with steel pins. Aerodynamic shape also adds stiffness