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4iiii Precision 3 Power Meter - Ultegra 8100


It's no easy feat to improve upon a power meter that was already one of the lightest, cheapest, and most accurate on the market, but the 4iiii Precision 3 has done just that.

Regardless of whether you are contesting Iron Man triathlons, stages of the Tour de France, or town-sign sprints during the weekend club run, the Precision 3 offers truly world-class technology, at an affordable price point.


As you’d expect, the 4iiii Precision 3 is feature packed and easy to install. It incorporates Bluetooth and ANT+ connectivity, so you can connect it to your choice of bike computer or indoor trainer. Pair it with a compatible device, and it'll work with a plethora of indoor training software, including TrainerRoad and Zwift.

Installation of the device is as simple as installing any Shimano left-side crank arm. The power meter arrives pre-attached to the Ultegra 8100 crank arm, all that's left for you to do is install it on your bike, as you would a regular crank arm. Once installed, follow the set-up instructions via the app, available on iOS and Android. With the app you can also update the firmware, check battery status, and calibrate your power meter.


In the previous iteration, the Precision already boasted a respectable 120-hour battery life. For the latest version, this has been increased to an industry-leading 800 hours. Operated by a simple to replace CR2032 battery, even the most dedicated cyclists will rarely need to replace the battery. Incredibly, despite this increase in battery life, the casing that houses the device is almost half as thick as previously, making it compatible with even more frames. Handily, LED lights have been added to indicate battery life, connectivity, and calibration status.


A power meter lives and dies by its accuracy and reliability; after all, there is little point in looking at data from a device that can't be trusted. Over the years, 4iiii have established themselves as a reputable player in the industry, and are well regarded for the accuracy and reliability of their devices.

As you'd expect, then, the Precision 3 is no different. Offering accuracy of +/-1%, there are few if any competitors on the market claiming anything better, and you can count on this accuracy to remain reliable. What’s more, with a IPX7 water resistance rating, you can ride into the depths of winter assured that your power meter will survive.

Product Features:

  • 800-hours battery life
  • LED lights to indicate – on (green), zero offset (blue), and low battery (red)
  • 3D Strain Gauge technology to deliver +/- 1% accuracy
  • Slimmed down design that fits virtually every frame
  • Three-year warranty
  • IPX7 water resistance rating
  • Weighs only nine grams
  • Backwards compatible with current Precision Drive Side Powermeter
  • Active temperate compensation
  • Over the air feature and firmware upgradability
  • Coin cell battery operated (CR2032)
  • Compatible with 3rd party training apps such as Zwift, TrainerRoad, SYSTM, and more


  • Accuracy: +/- 1%
  • Battery Type: CR2032 Coin Cell
  • Battery Life: 800 Hours
  • Waterproof Rating: Ipx7
  • Cadence Range: 30-170 RPM
  • Power Range: 0-4000 Watts
  • Length: 63.79mm
  • Width: 26.42mm
  • Height: 5.5mm
  • Weight: 9g
  • Operating Temperature: 0 to 50°C
  • Storage Temperature: -40 to 60°C
  • Communication Protocols: ANT+, Bluetooth®
  • Ultegra R8100
  • Precision 3
  • Road
  • Shimano
  • 4iiii

How long will it take to arrive?

Please check the stock availability notice on your item when placing your order. This item is:

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If I'm not completely happy with my item?

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