With all the accuracy and functionality of the DURA-ACE power meters, the ULTEGRA FC-R8100-P power meter comes in a more convenient package. Scientific training requires accurate measurements and ease of use, features offered by the new ULTEGRA R8100 power meter. Two-sided measurement has a maximum deviation of 2.0% and zero calibration is a quick and easy procedure. Perhaps even more importantly, the long battery life, easy charging and ANT+ and Bluetooth LE connectivity make using and recording workouts easier than ever. Features Integrated, waterproof and rechargeable lithium-ion battery Up to 300+ hours of battery life * Depending on ANT+/Bluetooth L settings Accurate data collection ±2.0% margin of error in effort measurement over the entire calibration range Unique effort meter Quick start Simple zero calibration with switch on transmitter Active temperature compensation Software automatically compensates for temperature variations Providing new force vector data makes it the optimal training tool for analysing and improving pedalling efficiency With SHIMANO CONNECT Lab, you can analyse your training and power data Cranks without chainring Technologies Hollowtech II Providing the best balance of stiffness, strength, weight and rotating performance The concept of Hollowtech II technology is focused on producing a superior crankset which will maximize a rider’s power transfer. The rigidity of the crankset ensures pedaling efficiency while its weight, a key element of the crankset, you want light, aids in cycling longer distances over which the rider needs to pedal more. Naturally, Shimano strove for the optimum balance between the conflicting needs of stiffness while producing a lightweight crank. Hollowtech technology is an ultra-lightweight hollow crankarm created by Shimano with the company’s own proprietary forging technology that also maintains rigidity. The addition of Hollowtech II technology integrates the bottom bracket axle with the right crankarm for more stiffness and a weight savings to achieve a high-dimensional balance. Its outboard bottom bracket bearing system provides better weight distribution and more pedaling stability, allowing for more efficient power transfer. The Hollowtech II crankset has been developed by pursuing the optimum balance of stiffness rotating performance in a lightweight and beautiful crankset design. High Precision Sealing Moreover, Hollowtech II crankset has a high-precision sealing in the bearing area to increase durability maintaining the excellent rotating performance for long periods. Hollowtech An ultra-light crankset not only reduces the weight of the bike, but also reduces the rotational mass, facilitating acceleration. The aim is to reduce the weight of the crankset without reducing its strength and stiffness. SHIMANO's advanced forging technology has solved this problem with the HOLLOWTECH crankset. As with high quality frame tubes, a hollow crank can provide incredible strength and stiffness with very little weight. Hollowglide Hollow technology on the outer chainring, the high-rigidity hollow structure reduces weight while maintaining rigidity. More efficient power transfer and more immediate and precise chainring.