Product details:

Offering the precision and functionality needed for scientific training, the Shimano Ultegra FC-R8100 Power Meter Crank Arm Set provides dual-sided measurement that is accurate within 1.5percent. Its long battery life, easy recharge, and ANT+ and Bluetooth LE connectivity makes using and recording your workouts easier than ever. Chainrings sold separately. Integrated, waterproof, and rechargeable Li-ion battery. Up to 300+ hours of ride time (depending on ANT+/Bluetooth LE settings). Accurate data collection. ±1.5percent strain gage accuracy throughout the entire calibration range (depending on ANT+/Bluetooth LE settings). Proprietary strain gauge. Quick and easy start-up process. Simple zero offset calibration with switch on transmitter. Active temperature compensation.Integrated waterproof and rechargeable Li-ion battery
Up to 300+ hours of ride time (depending on ANT+/Bluetooth LE settings)
Accurate data collection
±1.5% strain gage accuracy throughout the entire calibration range (depending on ANT+/Bluetooth LE settings)
Proprietary strain gauge
Quick and easy start-up process
Simple zero offset calibration with switch on transmitter
Active temperature compensation