Shimano Dura-Ace FC-9200-P Power Meter Chainset Working extensively with the world’s finest professional cycling teams, Shimano has created the Dura-Ace FC-9200-P Power Meter Chainset. Seamlessly integrated into both crank arms and completely sealed from the weather, the power measuring strain gauges are precisely calibrated to achieve power readings accurate to within +/-1.5%. Additionally, independent measurements from both legs are monitored, allowing the rider to address particular pedalling imbalances if necessary. The power readings are communicated in real-time to compatible bike computers via the wireless ANT+ and Bluetooth protocols, while the rechargeable internal battery can last for up to 300 hours of riding between charges. A simple zero offset calibration procedure ensures rides start with exceptional accuracy, and the active temperature compensation feature keeps power readings consistent through all conditions. HollowTech II aluminium crank arms are light but incredibly stiff, and the chainrings have refined tooth profiles to grant extra efficiency when used with a 12-speed chain. The HollowTech II 24mm diameter spindle finishes the design, for excellent power transfer and bottom bracket compatibility.