Shimano Ultegra FC-R8100-P Ultegra 12-speed double Power Meter chainset.

• The HollowTech II 12-speed Ultegra chainset with integrated power meter offers an ideal balance of light weight and stiffness, making it the perfect choice for both enthusiast and competitive riders
• Accurately calibrated strain gauges are integrated inside the crank arm, this provides a stable measurement system through rotation from both sides for extremely precise data
• +/-2% accuracy of strain gauge measured power
• Bluetooth and ANT+ with wireless firmware update and data acquisition system
• Easily rechargeable integrated battery with fully waterproof reliable electric system
• HollowGlide hollow outer chainring gives vast improvements in rigidity by virtually removing outer chainring flex and hugely improves shift performance, even under high load
• The chainring teeth have been developed to work in conjunction with 12-speed HG chains for increased contact to provide greater efficiency and improved power transfer
• Industry leading HollowTech II cold forged 4 arm hollow cranks have been evolved for maximum rigidity while reducing weight
• Wide gear pitch spacing increases clearance between chain and leading teeth to provide compatibility to frames with O.L.D. 135 / 142 mm
• A wide range of chainring options and crank arm lengths are available to meet the needs of all riders and racing disciplines
• HollowTech II integrated bottom bracket uses a wider bearing placement and larger axle diameter for increased stiffness and efficiency
• HollowTech II integrated bottom bracket seal design has minimal bearing interface ensuring smooth rolling and increased durability(sold separately)