Our first integrated power meter ensures extremely high data accuracy. The FC-R9100-P is the first power meter from Shimano as well as the first crank-integrated power meter on the market. It retains the unique asymmetrical spider design with four arms, but now includes a "brain" inside. The strain gauges are located on the crank arm. These work in perfect synchronization, allowing you to improve your performance with extremely accurate data. Reliable electric system Waterproof under all conditions Fast system start Easy reset to zero via switch on the transmitter