Crank up your performance with the Dura Ace FC-R9100-P Powermeter. The FC-R9100-P is seamlessly designed into the DURA-ACE HOLLOWTECH II crankset for world-class power measurement. Features dual-sided strain gauges internally hard wired for performance in any weather condition and accurate measurement regardless of pedaling position. Maintenance is simple with a single rechargeable battery powering the entire unit and wirelessly updated firmware. The DURA-ACE groupset was created with Shimano's ongoing passion for technology. All components are joined together to work as one, reinforcing each other for unparalleled performance and ultimate industry supremacy.