The Shimano Ultegra FC-R8100 Power Meter Crank Arm Set is your precision tool for training. Providing dual-sided measurement accurate within 1.5%, this crankset comes with an integrated, waterproof, and rechargeable Li-ion battery, ensuring up to 300+ hours of ride time. Enjoy accurate data collection with 1.5% strain gage accuracy, supported by ANT+ and Bluetooth LE connectivity. The proprietary strain gauge and quick start-up process enhance your training experience, making workouts easy to use and record.