4iiii Precision 3 Left-Side Power Meter (Black) (For Shimano) (175mm) (GRX RX810)

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Price: $384.99

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4iiii Precision 3 Left-Side Power Meter Description:

When you're working hard to push your fitness to the next level, you want a power meter that's reliable and accurate. The 4iiii Precision 3 power meter is designed for the long haul – with 800 hours of battery life, you will only have to swap batteries every year or two. For the data crunchers, the Precision 3 uses three strain gauges to measure changes in your pedal stroke output – a rare feature for left-side-only power meters. Guaranteeing accuracy, the Precision 3 has been third-party tested to verify a plus or minus 1% margin of error in the readings.

Available on a number of Shimano Hollowtech II crankarms (all Hollowtech II crankarms are interchangeable, however, you may want to choose a matching crankarm for aesthetic reasons). The Precision 3 power meter adds only 9g to the weight of these stock Shimano cranks.  

Note: Some bikes don't have enough clearance between the crankarm and frame for the Precision 3 power meter (especially gravel bikes with wide chainstays). Use 4iiii's clearance checker to verify fit.


  • Ride-ready left-side power meter
  • Up to 800 hours of battery life for years of riding
  • 3D Strain Gauge technology reveals power output changes over the full pedal stroke
  • +/-1% accuracy (3rd-party verified)
  • Compatible with ANT+ PWR and Bluetooth standards for compatibility with nearly all headunits and smartphones
  • Low profile design for better frame compatibility
  • IPX7 waterproof for reliability in the the toughest conditions 
  • Indicator light tells you when power meter is on, if you successfully calibrated it, or if the battery is low
  • Pre-installed on a brand-new Shimano Hollowtech II crankarm
  • All Hollowtech II crankarms are interchangeable, though colors and design vary by model


  • Accuracy: +/-1%
  • Battery Type: CR2032 Coin Cell
  • Battery Life: Up To 800 Hours
  • Waterproof Rating: IPX7
  • Cadence Range: 30 - 170 RPM
  • Power Range: 0 - 4000 W
  • Operating Temperature: 0 to 50°C (32 to 122°F)
  • Communication Protocols: ANT+, Bluetooth
  • Height: 5.5mm (Power Meter Beyond Crankarm)
  • Weight: 9g (Power Meter Only)

This product was added to our catalog on August 28, 2023