The Shimano Ultegra 8100 PRECISION 3+ Left-Side Power Meter delivers wattage, cadence, and calories burned directly to our head unit of choice. As the only crank-based power meter to use 3 strain gauges, all forces in our pedal stroke are measured with +/-1% accuracy and features an automatic terrain selector for responsive cadence and power feedback. From a steep climb up the canyon to a Zwift ride in our living room, this left-side power meter has us covered.