4iiii Precision Power Meter Shimano Ultegra R8000 172.5mm

Precision in name and in execution, this superb unit is the most accurate way to keep on top of your riding progress. This left-arm model is compatible with Shimano Ultegra FC-R8000 cranksets and provides instant cadence and power data right to your onboard computer or smartphone via ANT+ and Bluetooth. Weighing just 8g, it delivers output readings to within +/-1% accuracy, allowing for the correct adjustments to be made to keep you riding at peak performance. IPX7 waterproof rated and equipped with 100+ hours of battery life, the Precision is a stunning training aid for the performance-focused rider.